fix CI warning about node12 by updating actions/checkout version

Summary:
X-link: facebookincubator/velox#7071

fix CI warning about node12 by updating actions/checkout version

Update the actions/checkout version to fix build warning

X-link: facebook/sapling#749

Reviewed By: sggutier

Differential Revision: D50313430

Pulled By: genevievehelsel

fbshipit-source-id: 4d55d36f7509be51bb4e26728ddbce8e45faba40

Author: ahornby

build/fbcode_builder/getdeps.py

@@ -1023,7 +1023,7 @@ def write_job_for_platform(self, platform, args):  # noqa: C901
                 out.write("    - name: Disable autocrlf\n")
                 out.write("      run: git config --system core.autocrlf false\n")
 
-            out.write("    - uses: actions/checkout@v2\n")
+            out.write("    - uses: actions/checkout@v4\n")
 
             if build_opts.free_up_disk:
                 free_up_disk = "--free-up-disk "