build(ci): automatic update via CI

.github/workflows/auto-update.yml

@@ -0,0 +1,82 @@
+name: update-bot
+
+on:
+  schedule:
+    - cron: '30 20 * * *'
+
+env:
+  REGISTRY: ghcr.io
+  IMAGE_NAME: ${{ github.repository }}
+
+jobs:
+  check:
+    runs-on: ubuntu-latest
+    outputs:
+      is_new: ${{ steps.check_ver.outputs.is_new }}
+      version: ${{ steps.check_ver.outputs.version }}
+    steps:
+      - name: Check version
+        id: check_ver
+        run: |
+          get_ver() (curl -s "$@" | grep -Po "(\d+\.)+\d+\-r\d+" | head -1)
+          OLD_VER=$(get_ver ${GHCO_URL})
+          NEW_VER=$(get_ver ${ALPINE_PKG_URL})
+          if [ "$NEW_VER" != "$OLD_VER" ]; then
+            echo "::set-output name=is_new::true"
+          else
+            echo "::set-output name=is_new::false"
+          fi
+          echo "::set-output name=version::${NEW_VER}"
+        env:
+          ALPINE_PKG_URL: https://pkgs.alpinelinux.org/package/edge/testing/x86_64/qbittorrent-nox
+          GHCO_URL: https://github.com/mogeko/docker-qbittorrent/pkgs/container/qbittorrent
+
+  build:
+    runs-on: ubuntu-latest
+    needs: check
+    if: ${{ needs.check.outputs.is_new }}
+    permissions:
+      packages: write
+      contents: read
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v2
+        with:
+          fetch-depth: 0
+
+      - name: Log in to the Container registry
+        uses: docker/login-action@f054a8b539a109f9f41c372932f1ae047eff08c9
+        with:
+          registry: ${{ env.REGISTRY }}
+          username: ${{ github.actor }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Extract metadata (tags, labels) for Docker
+        id: meta
+        uses: docker/metadata-action@98669ae865ea3cffbcbaa878cf57c20bbf1c6c38
+        with:
+          images: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}
+          tags: |
+            type=edge
+            type=schedule,pattern={{date 'YYYYMMDD'}}
+            type=raw,${{ needs.check.outputs.version }}
+
+      - name: Build and push Docker image
+        id: build
+        uses: docker/build-push-action@ad44023a93711e3deb337508980b4b5e9bcdc5dc
+        with:
+          context: .
+          push: true
+          tags: ${{ steps.meta.outputs.tags }}
+          labels: ${{ steps.meta.outputs.labels }}
+          build-args: |
+            VERSION=${{ needs.check.outputs.version }}
+
+      - name: Save metadata
+        run: echo ${{ toJSON(steps.build.outputs.metadata) }} > ${{ github.workspace }}/meta.json
+
+      - name: Update metadata
+        uses: actions/upload-artifact@v2
+        with:
+          name: metadata
+          path: ${{ github.workspace }}/meta.json