Build Docker image for arm64 architecture (nightscout#7043)

* Build docker image for arm64 architecture

* Add `platforms` input

* Merge `master` and `dev` jobs together into one

* Run job on master or dev branch

.github/workflows/main.yml

@@ -40,14 +40,19 @@ jobs:
       - name: Send Coverage
         run: npm run-script coverage
 
-  publish_dev:
-    name: Publish dev branch to Docker Hub
+  publish:
+    name: Publish to Docker Hub
     needs: test
     runs-on: ubuntu-latest
-    if: github.ref == 'refs/heads/dev' && github.repository_owner == 'nightscout'
+    if: (github.ref == 'refs/heads/master' || github.ref == 'refs/heads/dev') && github.repository_owner == 'nightscout'
     env:
       DOCKER_IMAGE: nightscout/cgm-remote-monitor
+      PLATFORMS: linux/amd64,linux/arm64
     steps:
+      - name: Set up QEMU
+        uses: docker/setup-qemu-action@v1
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v1
       - name: Login to Docker Hub
         uses: docker/login-action@v1
         with:
@@ -57,37 +62,29 @@ jobs:
         if: success()
         uses: actions/checkout@v2
       - name: Build, tag and push the dev Docker image
-        if: success()
-        run: |
-          docker build --no-cache=true -t ${{ env.DOCKER_IMAGE }}:dev_${{ github.sha }} .
-          docker image push ${{ env.DOCKER_IMAGE }}:dev_${{ github.sha }}
-          docker tag ${{ env.DOCKER_IMAGE }}:dev_${{ github.sha }} ${{ env.DOCKER_IMAGE }}:latest_dev
-          docker image push ${{ env.DOCKER_IMAGE }}:latest_dev
-
-  publish_master:
-    name: Publish master branch to Docker Hub
-    needs: test
-    runs-on: ubuntu-latest
-    if: github.ref == 'refs/heads/master' && github.repository_owner == 'nightscout'
-    env:
-      DOCKER_IMAGE: nightscout/cgm-remote-monitor
-    steps:
-      - name: Login to Docker Hub
-        uses: docker/login-action@v1
+        if: success() && github.ref == 'refs/heads/dev'
+        uses: docker/build-push-action@v2
         with:
-          username: ${{ secrets.DOCKER_USER }}
-          password: ${{ secrets.DOCKER_PASS }}
-      - name: Clean git Checkout
-        if: success()
-        uses: actions/checkout@v2
-      - name: get-npm-version
-        if: success()
+          context: .
+          push: true
+          no-cache: true
+          platforms: ${{ env.PLATFORMS }}
+          tags: |
+            ${{ env.DOCKER_IMAGE }}:dev_${{ github.sha }}
+            ${{ env.DOCKER_IMAGE }}:latest_dev
+
+      - name: Get Nightscout release version
+        if: success() && github.ref == 'refs/heads/master'
         id: package-version
         uses: martinbeentjes/npm-get-version-action@master
       - name: Build, tag and push the master Docker image
-        if: success()
-        run: |
-          docker build --no-cache=true -t ${{ env.DOCKER_IMAGE }}:${{ steps.package-version.outputs.current-version }} .
-          docker image push ${{ env.DOCKER_IMAGE }}:${{ steps.package-version.outputs.current-version }}
-          docker tag ${{ env.DOCKER_IMAGE }}:${{ steps.package-version.outputs.current-version }} ${{ env.DOCKER_IMAGE }}:latest
-          docker image push ${{ env.DOCKER_IMAGE }}:latest
+        if: success() && github.ref == 'refs/heads/master'
+        uses: docker/build-push-action@v2
+        with:
+          context: .
+          push: true
+          no-cache: true
+          platforms: ${{ env.PLATFORMS }}
+          tags: |
+            ${{ env.DOCKER_IMAGE }}:${{ steps.package-version.outputs.current-version }}
+            ${{ env.DOCKER_IMAGE }}:latest