Bump docker/build-push-action from 5 to 6 (#34)

Author: dependabot[bot]

.github/workflows/docker.yml

@@ -41,7 +41,7 @@ jobs:
           tags: |
             type=match,pattern=v(.*),group=1
             type=ref,event=branch
-      - uses: docker/build-push-action@v5
+      - uses: docker/build-push-action@v6
         with:
           context: .
           platforms: linux/amd64,linux/arm64,linux/arm/v7