Update GH actions to multi arch (arm64) (#1614)

add arm64 to the docker build
add the package to ghcr.io (github container registery)
this will make it so users can run matterbridge:latest and it will work on both amd64 & arm64

.github/workflows/docker.yml

@@ -20,6 +20,8 @@ jobs:
       -
         name: Set up QEMU
         uses: docker/setup-qemu-action@v1
+        with:
+          platforms: amd64,arm64
       -
         name: Set up Docker Buildx
         uses: docker/setup-buildx-action@v1
@@ -45,12 +47,21 @@ jobs:
         with:
           username: ${{ secrets.DOCKERHUB_USERNAME }}
           password: ${{ secrets.DOCKERHUB_TOKEN }}
+      - 
+        name: Log into registry ghcr.io
+        uses: docker/login-action@v1
+        if: github.event_name != 'pull_request'
+        with:
+          registry: ghcr.io
+          username: ${{ github.repository_owner }}
+          password: ${{ secrets.GITHUB_TOKEN }}
       -
         name: Build and push
         id: docker_build
         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 }}