arm64 and amd64 image support (#88)

* Ability to build arm7 docker image using buildx

* Build arm64 and amd64 images

.github/workflows/ci.yml

@@ -38,6 +38,12 @@ jobs:
         uses: actions/checkout@v2
         with:
           fetch-depth: 0
+      -
+        name: Set up QEMU
+        uses: docker/setup-qemu-action@v1
+      -
+        name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v1
       -
         name: Docker meta
         id: meta
@@ -56,6 +62,7 @@ jobs:
         uses: docker/build-push-action@v2
         with:
           context: .
+          platforms: linux/amd64,linux/arm64
           push: ${{ github.event_name != 'pull_request' }}
           tags: ${{ steps.meta.outputs.tags }}
           labels: ${{ steps.meta.outputs.labels }}