grab workflow from #44 but use GITHUB_TOKEN instead of PAT

Author: trashhalo

.github/workflows/publish.yml

@@ -0,0 +1,63 @@
+name: Publish Docker Image
+
+on:
+  release:
+    types: [published]
+
+jobs:
+  publish:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Get image tag
+        id: image_tag
+        run: echo ::set-output name=tag::${GITHUB_REF:10}
+
+      - name: Checkout
+        uses: actions/checkout@v2
+
+      - name: Create Docker context
+        run: docker context create mycontext
+
+      - name: Set up Docker Buildx
+        id: buildx
+        uses: docker/setup-buildx-action@v1
+        with:
+          endpoint: mycontext
+
+      - name: Cache Docker layers
+        uses: actions/cache@v2
+        with:
+          path: /tmp/.buildx-cache
+          key: ${{ runner.os }}-buildx-${{ github.sha }}
+          restore-keys: |
+            ${{ runner.os }}-buildx-
+
+      - name: Login to GHCR
+        uses: docker/login-action@v1
+        with:
+          registry: ghcr.io
+          username: ${{ github.actor }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Get repo in lowercase
+        id: repo_name
+        run: echo ::set-output name=repo::$(echo ${{ github.repository }} | tr '[:upper:]' '[:lower:]')
+
+      - name: Build & push image
+        uses: docker/build-push-action@v2
+        with:
+          context: .
+          builder: ${{ steps.buildx.outputs.name }}
+          push: true
+          tags: ghcr.io/${{ steps.repo_name.outputs.repo }}:${{ steps.image_tag.outputs.tag }},ghcr.io/${{ steps.repo_name.outputs.repo }}:latest
+          cache-from: type=local,src=/tmp/.buildx-cache
+          cache-to: type=local,dest=/tmp/.buildx-cache-new,mode=max
+
+        # Temp fix
+        # https://github.com/docker/build-push-action/issues/252
+        # https://github.com/moby/buildkit/issues/1896
+      - name: Move cache
+        run: |
+          rm -rf /tmp/.buildx-cache
+          mv /tmp/.buildx-cache-new /tmp/.buildx-cache