build: add docker arm image

.github/workflows/docker.yml

@@ -10,6 +10,8 @@ jobs:
     docker:
         runs-on: ubuntu-latest
         steps:
+            - name: Set up QEMU
+              uses: docker/setup-qemu-action@v2
             - name: Set up Docker Buildx
               uses: docker/setup-buildx-action@v2
             - name: Login to Docker Hub
@@ -25,4 +27,5 @@ jobs:
               uses: docker/build-push-action@v3
               with:
                   push: true
+                  platforms: linux/amd64,linux/arm64
                   tags: peerjs/peerjs-server-test:nightly