Push to dockerhub on version tag (#83)

Automate the longest leg of our umbrel release process

.github/workflows/docker-release.yml

@@ -0,0 +1,26 @@
+on:
+  push:
+    tags:
+      - 'v*.*.*'
+
+env:
+  CARGO_TERM_COLOR: always
+
+jobs:
+  buildx:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - name: Set env
+        run: echo "RELEASE_VERSION=${GITHUB_REF#refs/*/}" >> $GITHUB_ENV
+      - name: Log in to Docker Hub
+        uses: docker/login-action@v2
+        with:
+          username: chaincase
+          password: ${{ secrets.DOCKERHUB_TOKEN }}
+      - name: Set up QEMU
+        uses: docker/setup-qemu-action@v2
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v2
+      - name: Dockerize
+        run: docker buildx build --platform linux/arm64,linux/amd64 --tag chaincase/nolooking:${{ env.RELEASE_VERSION }} --output type=registry .