Re-enable buildx

Author: Jennings Zhang

.github/workflows/ci.yml

@@ -29,15 +29,9 @@ jobs:
           echo $dock_image
           echo "::set-output name=dock_image::$dock_image"
           echo "::set-output name=repo::$repo"
-      - uses: actions/checkout@v2
 
-#       # QEMU is for emulating non-x86_64 platforms
 #       - uses: docker/setup-qemu-action@v1
-#       # buildx is the next-generation docker image builder
-#       - uses: docker/setup-buildx-action@v1
-#         with:
-#           driver-opts: network=host
-      # save some time during rebuilds
+      - uses: docker/setup-buildx-action@v1
       - name: Cache Docker layers
         uses: actions/cache@v2
         with:
@@ -64,8 +58,6 @@ jobs:
         uses: docker/build-push-action@v2
         id: docker_build
         with:
-          context: .
-          file: ./Dockerfile
           tags: |
             docker.io/${{ steps.determine.outputs.dock_image }}
             ghcr.io/${{ steps.determine.outputs.dock_image }}