Set github-actions identity as defautl committer (#11987)

.github/workflows/push-update-security-config.yaml

@@ -25,6 +25,12 @@ jobs:
 
     steps:
       - uses: actions/checkout@v4
+        # Setup git config with default actions information to prevent error "Unknown committer"
+        # See https://github.com/actions/checkout/issues/13#issuecomment-2207006934
+      - name: Setup git config
+        run: |
+          git config user.name github-actions
+          git config user.email github-actions@github.com
       - name: Authenticate in GCP
         id: 'auth'
         uses: 'google-github-actions/auth@v2'