chore(deps): update docker/build-push-action action to v6

Author: renovate[bot]

.github/workflows/pr-checks.yml

@@ -69,7 +69,7 @@ jobs:
         id: buildx
         uses: docker/setup-buildx-action@v3
       - name: Build
-        uses: docker/build-push-action@v4
+        uses: docker/build-push-action@v6
         with:
           builder: ${{ steps.buildx.outputs.name }}
           context: .

.github/workflows/release-please.yml

@@ -74,7 +74,7 @@ jobs:
         uses: docker/setup-buildx-action@master
 
       - name: Build
-        uses: docker/build-push-action@v4
+        uses: docker/build-push-action@v6
         with:
           builder: ${{ steps.buildx.outputs.name }}
           context: .