Update docker-push-posthog.yml

Author: choxx

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

@@ -38,6 +38,7 @@ jobs:
         uses: docker/build-push-action@v2
         with:
           context: ./
+          file: ./build/Dockerfile.Posthog
           push: true
           tags: ${{ steps.meta.outputs.tags }}