[ci] Fix bump-homebrew-formula-action step

COMITTER_TOKEN only has `public_repo` scope, so it can't verify the SHA2
sum of the download from under the SAML-protected `github` org

340b79ac78/checks?check_suite_id=412124491

.github/workflows/release.yml

@@ -28,3 +28,4 @@ jobs:
         formula-name: hub
       env:
         COMMITTER_TOKEN: ${{ secrets.COMMITTER_TOKEN }}
+        GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}