[CI] detect and skip rest of action when nothing to commit

Author: glpatcern

.github/workflows/build-and-publish.yml

@@ -38,6 +38,11 @@ jobs:
           git add .
           git commit -m 'Synced to https://github.com/cern-eos/grpc-proto/tree/${{ github.sha }}'
           git push origin main
+          if [[ $? -ne 0 ]]; then
+            echo "The committed changes (if any) did not update the protobufs, nothing more to do"
+            gh run cancel ${{ github.run_id }}
+            gh run watch ${{ github.run_id }}
+          fi
       - name: setup-buf
         uses: bufbuild/buf-setup-action@v1
       - name: push-buf