Add workflow to rebuild master on cron

.github/workflows/build-images-cron.yml

@@ -0,0 +1,62 @@
+---
+
+name: Build Images Cron
+
+# Rebuild images from master branch every Sunday
+
+on:
+  schedule:
+    - cron: "0 0 * * 0"
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v2
+        with:
+          ref: master
+
+      - name: Get build tag
+        id: get_build_tag
+        # You must push tags first before pushing refs, otherwise you'll never build an image
+        # tagged with a git tag.
+        run: |
+          if [[ "${GITHUB_REF}" == refs/tags/* ]]; then
+            TAG="$(echo ${GITHUB_REF#refs/tags/} | sed 's/^v//g')"
+          else
+            TAG="$(echo ${GITHUB_REF#refs/heads/} | tr '/-' '_')-${GITHUB_SHA:0:7}-$(date -u +'%Y%m%d%H%M')"
+          fi
+          echo "TAG: ${TAG}"
+          echo "::set-output name=tag::${TAG}"
+
+      - name: Set up Docker Buildx
+        id: buildx
+        uses: docker/setup-buildx-action@v1
+
+      - 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 Docker Hub
+        uses: docker/login-action@v1
+        with:
+          username: ${{ secrets.PANUBUILD_DOCKERHUB_USERNAME }}
+          password: ${{ secrets.PANUBUILD_DOCKERHUB_TOKEN }}
+
+      - name: Build and Push
+        uses: docker/build-push-action@v2
+        with:
+          builder: ${{ steps.buildx.outputs.name }}
+          context: .
+          file: Dockerfile
+          push: true
+          cache-from: type=local,src=/tmp/.buildx-cache
+          cache-to: type=local,mode=max,dest=/tmp/.buildx-cache
+          tags: |
+            panubo/sshd:latest
+            panubo/sshd:${{ steps.get_build_tag.outputs.tag }}