Proper branch name for mvfst

Summary:
Need to fix branch name for OSS mvfst so CI continues on.

Ran opensource/fbcode_builder/getdeps/facebook/update-all-github-actions.sh

Reviewed By: lnicco

Differential Revision: D32041656

fbshipit-source-id: f72aab91a3084814a5d3fa8643ae5f405908c313

build/fbcode_builder/getdeps.py

@@ -921,7 +921,7 @@ jobs:
                 f"--final-install-prefix /usr/local\n"
             )
 
-            out.write("    - uses: actions/upload-artifact@master\n")
+            out.write("    - uses: actions/upload-artifact@%s\n" % args.main_branch)
             out.write("      with:\n")
             out.write("        name: %s\n" % manifest.name)
             out.write("        path: _artifacts\n")