Update docker/build-push-action action to v7 (#114)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

.github/workflows/backend.yaml

@@ -61,7 +61,7 @@ jobs:
             type=raw,value=latest,enable={{is_default_branch}}
 
       - name: Build and push
-        uses: docker/build-push-action@v6
+        uses: docker/build-push-action@v7
         with:
           context: ./backend
           platforms: linux/amd64,linux/arm64

.github/workflows/frontend.yaml

@@ -48,7 +48,7 @@ jobs:
             type=raw,value=latest,enable={{is_default_branch}}
 
       - name: Build and push
-        uses: docker/build-push-action@v6
+        uses: docker/build-push-action@v7
         with:
           context: ./frontend
           platforms: linux/amd64,linux/arm64