Bump docker/build-push-action from 5 to 6

Bumps [docker/build-push-action](https://github.com/docker/build-push-action) from 5 to 6.
- [Release notes](https://github.com/docker/build-push-action/releases)
- [Commits](docker/build-push-action@v5...v6)

---
updated-dependencies:
- dependency-name: docker/build-push-action
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <[email protected]>

.github/workflows/docker-nginx.yml

@@ -47,7 +47,7 @@ jobs:
           DOCKERFILE=$(echo ".docker/Dockerfile.nginx")
           echo "DOCKERFILE=$DOCKERFILE" >> $GITHUB_OUTPUT
       - name: Build container image
-        uses: docker/build-push-action@v5
+        uses: docker/build-push-action@v6
         with:
           push: false
           context: .docker/
@@ -58,7 +58,7 @@ jobs:
           cache-from: type=local,src=/tmp/.buildx-cache
           cache-to: type=local,dest=/tmp/.buildx-cache-new
       - name: Push container image
-        uses: docker/build-push-action@v5
+        uses: docker/build-push-action@v6
         if: github.ref == 'refs/heads/main'
         with:
           push: true

.github/workflows/docker-php.yml

@@ -55,7 +55,7 @@ jobs:
           DOCKERFILE=$([[ -f ".docker/$NAME/Dockerfile" ]] && echo ".docker/$NAME/Dockerfile" || echo ".docker/Dockerfile.$NAME")
           echo "DOCKERFILE=$DOCKERFILE" >> $GITHUB_OUTPUT
       - name: Build container image
-        uses: docker/build-push-action@v5
+        uses: docker/build-push-action@v6
         with:
           push: false
           context: .docker/
@@ -66,7 +66,7 @@ jobs:
           cache-from: type=local,src=/tmp/.buildx-cache
           cache-to: type=local,dest=/tmp/.buildx-cache-new
       - name: Push container image
-        uses: docker/build-push-action@v5
+        uses: docker/build-push-action@v6
         if: github.ref == 'refs/heads/main'
         with:
           push: true