Update docker/build-push-action action to v7

Author: renovate[bot]

.github/workflows/webapp-dev.yml

@@ -46,7 +46,7 @@ jobs:
         password: ${{ secrets.GHCR_TOKEN }}
 
     - name: Build and push image
-      uses: docker/build-push-action@v6
+      uses: docker/build-push-action@v7
       with:
         push: true
         platforms: linux/amd64,linux/arm64