update to checkout@v2

Summary:
checkout@v2 is the current action version, and the old one may have
security issues. Let's just run with the latest version.

Reviewed By: ahornby

Differential Revision: D33834847

fbshipit-source-id: fba0733577bf23c208c9824aa3815bd01a813d9a

.github/workflows/getdeps_linux.yml

@@ -14,7 +14,7 @@ jobs:
   build:
     runs-on: ubuntu-18.04
     steps:
-    - uses: actions/checkout@v1
+    - uses: actions/checkout@v2
     - name: Fetch boost
       run: python3 build/fbcode_builder/getdeps.py fetch --no-tests boost
     - name: Fetch ninja

.github/workflows/getdeps_mac.yml

@@ -14,7 +14,7 @@ jobs:
   build:
     runs-on: macOS-latest
     steps:
-    - uses: actions/checkout@v1
+    - uses: actions/checkout@v2
     - name: Fetch boost
       run: python3 build/fbcode_builder/getdeps.py fetch --no-tests boost
     - name: Fetch openssl

.github/workflows/getdeps_windows.yml

@@ -14,7 +14,7 @@ jobs:
   build:
     runs-on: windows-2016
     steps:
-    - uses: actions/checkout@v1
+    - uses: actions/checkout@v2
     - name: Export boost environment
       run: "echo BOOST_ROOT=%BOOST_ROOT_1_69_0% >> %GITHUB_ENV%"
       shell: cmd

build/fbcode_builder/getdeps.py

@@ -934,7 +934,7 @@ jobs:
             out.write("  build:\n")
             out.write("    runs-on: %s\n" % runs_on)
             out.write("    steps:\n")
-            out.write("    - uses: actions/checkout@v1\n")
+            out.write("    - uses: actions/checkout@v2\n")
 
             if build_opts.is_windows():
                 # cmake relies on BOOST_ROOT but GH deliberately don't set it in order