SRE-2829: Pin build-push-action (#40)

Author: timm088

.github/actions/push/action.yaml

@@ -67,7 +67,7 @@ runs:
         endpoint: builders
 
     - name: Build and push
-      uses: docker/build-push-action@v4
+      uses: docker/build-push-action@471d1dc4e07e5cdedd4c2171150001c434f0b7a4 # [email protected]
       with:
         context: .
         platforms: linux/amd64