chore(deps): update docker/build-push-action action to v6.15.0 (#945)

| datasource  | package                  | from    | to      |
| ----------- | ------------------------ | ------- | ------- |
| github-tags | docker/build-push-action | v6.14.0 | v6.15.0 |

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

Author: renovate[bot]

.github/workflows/build.yml

@@ -130,7 +130,7 @@ jobs:
           password: ${{ secrets.GITHUB_TOKEN }}
 
       - name: Build container images
-        uses: docker/build-push-action@0adf9959216b96bec444f325f1e493d4aa344497 # v6.14.0
+        uses: docker/build-push-action@471d1dc4e07e5cdedd4c2171150001c434f0b7a4 # v6.15.0
         with:
           platforms: linux/amd64,linux/arm/v7,linux/arm64
           tags: ${{ env.IMAGE_NAME }}:latest
@@ -144,7 +144,7 @@ jobs:
 
       - name: Push container images
         if: ${{ env.IMAGE_TAG != '' }}
-        uses: docker/build-push-action@0adf9959216b96bec444f325f1e493d4aa344497 # v6.14.0
+        uses: docker/build-push-action@471d1dc4e07e5cdedd4c2171150001c434f0b7a4 # v6.15.0
         with:
           platforms: linux/amd64,linux/arm/v7,linux/arm64
           push: true