Update docker/build-push-action action to v6

Author: renovate[bot]

.github/workflows/master-container-publish.yml

@@ -79,7 +79,7 @@ jobs:
 
       - name: Build and push Docker image
         id: build
-        uses: docker/build-push-action@v5
+        uses: docker/build-push-action@v6
         with:
           platforms: linux/amd64,linux/arm64
           context: .

.github/workflows/pr-preview.yml

@@ -86,7 +86,7 @@ jobs:
 
       - name: Build and push Docker image
         id: build
-        uses: docker/build-push-action@v5
+        uses: docker/build-push-action@v6
         with:
           context: .
           push: true