Add path to Dockerfile in Docker build GitHub Action workflow.

Author: Potherca

.github/workflows/docker-build-push.yml

@@ -49,6 +49,7 @@ jobs:
         uses: docker/build-push-action@v4
         with:
           context: .
+          file: ./docker/solid.Dockerfile
           platforms: linux/amd64,linux/arm64
           push: true
           tags: "ghcr.io/${{ github.repository }}:${{ env.TAG }}"