configure github actions CI (#1228)

Summary:
This commit configures CI for Windows, macOS and Linux using the
new GitHub Actions CI service.

The configuration was generated via:

```
build/fbcode_builder/getdeps.py generate-github-actions --output-file .github/workflows/main.yml folly
```
Pull Request resolved: https://github.com/facebook/folly/pull/1228

Reviewed By: yfeldblum

Differential Revision: D17454557

Pulled By: wez

fbshipit-source-id: a99261ee312d4093031cf6fad5832eacb1be1d97

.github/workflows/main.yml

+# This file was @generated by getdeps.py
+
+name: CI
+
+on:
+  push:
+    branches:
+    - master
+  pull_request:
+    branches:
+    - master
+
+jobs:
+  linux:
+    runs-on: ubuntu-18.04
+    steps:
+    - uses: actions/checkout@v1
+    - name: Fetch boost
+      run: python build/fbcode_builder/getdeps.py fetch --no-tests boost
+    - name: Fetch ninja
+      run: python build/fbcode_builder/getdeps.py fetch --no-tests ninja
+    - name: Fetch cmake
+      run: python build/fbcode_builder/getdeps.py fetch --no-tests cmake
+    - name: Fetch double-conversion
+      run: python build/fbcode_builder/getdeps.py fetch --no-tests double-conversion
+    - name: Fetch fmt
+      run: python build/fbcode_builder/getdeps.py fetch --no-tests fmt
+    - name: Fetch gflags
+      run: python build/fbcode_builder/getdeps.py fetch --no-tests gflags
+    - name: Fetch glog
+      run: python build/fbcode_builder/getdeps.py fetch --no-tests glog
+    - name: Fetch googletest
+      run: python build/fbcode_builder/getdeps.py fetch --no-tests googletest
+    - name: Fetch libevent
+      run: python build/fbcode_builder/getdeps.py fetch --no-tests libevent
+    - name: Fetch snappy
+      run: python build/fbcode_builder/getdeps.py fetch --no-tests snappy
+    - name: Fetch zstd
+      run: python build/fbcode_builder/getdeps.py fetch --no-tests zstd
+    - name: Build boost
+      run: python build/fbcode_builder/getdeps.py build --no-tests boost
+    - name: Build ninja
+      run: python build/fbcode_builder/getdeps.py build --no-tests ninja
+    - name: Build cmake
+      run: python build/fbcode_builder/getdeps.py build --no-tests cmake
+    - name: Build double-conversion
+      run: python build/fbcode_builder/getdeps.py build --no-tests double-conversion
+    - name: Build fmt
+      run: python build/fbcode_builder/getdeps.py build --no-tests fmt
+    - name: Build gflags
+      run: python build/fbcode_builder/getdeps.py build --no-tests gflags
+    - name: Build glog
+      run: python build/fbcode_builder/getdeps.py build --no-tests glog
+    - name: Build googletest
+      run: python build/fbcode_builder/getdeps.py build --no-tests googletest
+    - name: Build libevent
+      run: python build/fbcode_builder/getdeps.py build --no-tests libevent
+    - name: Build snappy
+      run: python build/fbcode_builder/getdeps.py build --no-tests snappy
+    - name: Build zstd
+      run: python build/fbcode_builder/getdeps.py build --no-tests zstd
+    - name: Build folly
+      run: python build/fbcode_builder/getdeps.py build --src-dir=. folly
+    - name: Test folly
+      run: python build/fbcode_builder/getdeps.py test --src-dir=. folly
+  mac:
+    runs-on: macOS-latest
+    steps:
+    - uses: actions/checkout@v1
+    - name: Fetch boost
+      run: python build/fbcode_builder/getdeps.py fetch --no-tests boost
+    - name: Fetch openssl
+      run: python build/fbcode_builder/getdeps.py fetch --no-tests openssl
+    - name: Fetch ninja
+      run: python build/fbcode_builder/getdeps.py fetch --no-tests ninja
+    - name: Fetch cmake
+      run: python build/fbcode_builder/getdeps.py fetch --no-tests cmake
+    - name: Fetch double-conversion
+      run: python build/fbcode_builder/getdeps.py fetch --no-tests double-conversion
+    - name: Fetch fmt
+      run: python build/fbcode_builder/getdeps.py fetch --no-tests fmt
+    - name: Fetch gflags
+      run: python build/fbcode_builder/getdeps.py fetch --no-tests gflags
+    - name: Fetch glog
+      run: python build/fbcode_builder/getdeps.py fetch --no-tests glog
+    - name: Fetch googletest
+      run: python build/fbcode_builder/getdeps.py fetch --no-tests googletest
+    - name: Fetch libevent
+      run: python build/fbcode_builder/getdeps.py fetch --no-tests libevent
+    - name: Fetch snappy
+      run: python build/fbcode_builder/getdeps.py fetch --no-tests snappy
+    - name: Fetch zstd
+      run: python build/fbcode_builder/getdeps.py fetch --no-tests zstd
+    - name: Build boost
+      run: python build/fbcode_builder/getdeps.py build --no-tests boost
+    - name: Build openssl
+      run: python build/fbcode_builder/getdeps.py build --no-tests openssl
+    - name: Build ninja
+      run: python build/fbcode_builder/getdeps.py build --no-tests ninja
+    - name: Build cmake
+      run: python build/fbcode_builder/getdeps.py build --no-tests cmake
+    - name: Build double-conversion
+      run: python build/fbcode_builder/getdeps.py build --no-tests double-conversion
+    - name: Build fmt
+      run: python build/fbcode_builder/getdeps.py build --no-tests fmt
+    - name: Build gflags
+      run: python build/fbcode_builder/getdeps.py build --no-tests gflags
+    - name: Build glog
+      run: python build/fbcode_builder/getdeps.py build --no-tests glog
+    - name: Build googletest
+      run: python build/fbcode_builder/getdeps.py build --no-tests googletest
+    - name: Build libevent
+      run: python build/fbcode_builder/getdeps.py build --no-tests libevent
+    - name: Build snappy
+      run: python build/fbcode_builder/getdeps.py build --no-tests snappy
+    - name: Build zstd
+      run: python build/fbcode_builder/getdeps.py build --no-tests zstd
+    - name: Build folly
+      run: python build/fbcode_builder/getdeps.py build --src-dir=. folly
+    - name: Test folly
+      run: python build/fbcode_builder/getdeps.py test --src-dir=. folly
+  windows:
+    runs-on: windows-2016
+    steps:
+    - uses: actions/checkout@v1
+    - name: Fetch boost
+      run: python build/fbcode_builder/getdeps.py fetch --no-tests boost
+    - name: Fetch perl
+      run: python build/fbcode_builder/getdeps.py fetch --no-tests perl
+    - name: Fetch openssl
+      run: python build/fbcode_builder/getdeps.py fetch --no-tests openssl
+    - name: Fetch ninja
+      run: python build/fbcode_builder/getdeps.py fetch --no-tests ninja
+    - name: Fetch cmake
+      run: python build/fbcode_builder/getdeps.py fetch --no-tests cmake
+    - name: Fetch double-conversion
+      run: python build/fbcode_builder/getdeps.py fetch --no-tests double-conversion
+    - name: Fetch fmt
+      run: python build/fbcode_builder/getdeps.py fetch --no-tests fmt
+    - name: Fetch gflags
+      run: python build/fbcode_builder/getdeps.py fetch --no-tests gflags
+    - name: Fetch glog
+      run: python build/fbcode_builder/getdeps.py fetch --no-tests glog
+    - name: Fetch googletest
+      run: python build/fbcode_builder/getdeps.py fetch --no-tests googletest
+    - name: Fetch libevent
+      run: python build/fbcode_builder/getdeps.py fetch --no-tests libevent
+    - name: Fetch snappy
+      run: python build/fbcode_builder/getdeps.py fetch --no-tests snappy
+    - name: Fetch zlib
+      run: python build/fbcode_builder/getdeps.py fetch --no-tests zlib
+    - name: Fetch zstd
+      run: python build/fbcode_builder/getdeps.py fetch --no-tests zstd
+    - name: Build boost
+      run: python build/fbcode_builder/getdeps.py build --no-tests boost
+    - name: Build perl
+      run: python build/fbcode_builder/getdeps.py build --no-tests perl
+    - name: Build openssl
+      run: python build/fbcode_builder/getdeps.py build --no-tests openssl
+    - name: Build ninja
+      run: python build/fbcode_builder/getdeps.py build --no-tests ninja
+    - name: Build cmake
+      run: python build/fbcode_builder/getdeps.py build --no-tests cmake
+    - name: Build double-conversion
+      run: python build/fbcode_builder/getdeps.py build --no-tests double-conversion
+    - name: Build fmt
+      run: python build/fbcode_builder/getdeps.py build --no-tests fmt
+    - name: Build gflags
+      run: python build/fbcode_builder/getdeps.py build --no-tests gflags
+    - name: Build glog
+      run: python build/fbcode_builder/getdeps.py build --no-tests glog
+    - name: Build googletest
+      run: python build/fbcode_builder/getdeps.py build --no-tests googletest
+    - name: Build libevent
+      run: python build/fbcode_builder/getdeps.py build --no-tests libevent
+    - name: Build snappy
+      run: python build/fbcode_builder/getdeps.py build --no-tests snappy
+    - name: Build zlib
+      run: python build/fbcode_builder/getdeps.py build --no-tests zlib
+    - name: Build zstd
+      run: python build/fbcode_builder/getdeps.py build --no-tests zstd
+    - name: Build folly
+      run: python build/fbcode_builder/getdeps.py build --src-dir=. folly
+    - name: Test folly
+      run: python build/fbcode_builder/getdeps.py test --src-dir=. folly