fix docker login

.github/workflows/container_foundationdb_version.yml

@@ -132,6 +132,7 @@ jobs:
         uses: docker/setup-buildx-action@v3
 
       - name: Login to Docker Hub
+        if: github.event_name != 'pull_request'
         uses: docker/login-action@v3
         with:
           username: ${{ secrets.DOCKER_USERNAME }}