ci:cd/ Improve GitHub Actions workflow (#34)

* ci/cd: Add dependabot.yml
* ci/cd: Update build-and-test.yml script
* ci/cd: Update publish.yml script
* doc: Update README.md

.github/workflows/build-and-test.yml

@@ -0,0 +1,113 @@
+name: Build and test Docker image
+
+on:
+  pull_request:
+    branches:
+      - master
+
+env:
+  IMAGE_NAME: localhost:5000/cdalvaro/docker-salt-master:ci
+  REGISTRY_PATH: ${{ github.workspace }}/registry
+  CACHE_PATH: /tmp/.buildx-docker-salt-master-cache
+
+jobs:
+  build:
+    name: Build
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v2
+
+      - name: Set up QEMU
+        uses: docker/setup-qemu-action@v1
+
+      - name: Start Docker registry
+        run: |
+          docker run -d -p 5000:5000 -v ${REGISTRY_PATH}:/var/lib/registry --name registry registry:2
+
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v1
+        with:
+          driver-opts: network=host
+
+      - name: Cache Docker layers
+        uses: actions/cache@v2
+        with:
+          path: ${{ env.CACHE_PATH }}
+          key: ${{ runner.os }}-buildx-${{ github.sha }}
+          restore-keys: |
+            ${{ runner.os }}-buildx-
+
+      - name: Build docker-salt-master image
+        uses: docker/build-push-action@v2
+        with:
+          context: .
+          file: ./Dockerfile
+          platforms: linux/amd64,linux/arm64
+          cache-from: type=local,src=${{ env.CACHE_PATH }}
+          cache-to: type=local,dest=${{ env.CACHE_PATH }}
+          push: true
+          tags: ${{ env.IMAGE_NAME }}
+
+      - name: Stop Docker registry
+        run: docker stop registry
+
+      - name: Upload Docker registry data for testing
+        uses: actions/upload-artifact@v2
+        with:
+          name: docker-registry-data
+          path: ${{ env.REGISTRY_PATH }}/
+
+  test:
+    name: Test
+    runs-on: ubuntu-latest
+    needs: build
+    strategy:
+      matrix:
+        platform: [linux/amd64, linux/arm64]
+    env:
+      DOCKER_CLI_EXPERIMENTAL: enabled
+    steps:
+      - name: Download Docker registry data from build job
+        uses: actions/download-artifact@v2
+        with:
+          name: docker-registry-data
+          path: ${{ env.REGISTRY_PATH }}
+
+      - name: Enable Docker experimental
+        run: |
+          # Enable docker daemon experimental support.
+          echo '{"experimental": true}' | sudo tee /etc/docker/daemon.json
+          sudo systemctl restart docker
+          # Install QEMU multi-architecture support for docker buildx.
+          docker run --rm --privileged multiarch/qemu-user-static --reset -p yes
+
+      - name: Start Docker registry
+        run: |
+          docker run -d -p 5000:5000 -v ${REGISTRY_PATH}:/var/lib/registry --name registry registry:2
+
+      - name: Docker inspect
+        run: docker buildx imagetools inspect ${IMAGE_NAME}
+
+      - name: Import Docker images
+        run: docker pull --platform ${{ matrix.platform }} ${IMAGE_NAME}
+
+      - name: Launch docker container
+        run: docker run --rm -d --name saltstack_master ${IMAGE_NAME}
+
+      - name: Show container info
+        run: docker container ls
+
+      - name: Wait for salt-master bootup
+        run: sleep 20
+
+      - name: Show salt versions
+        run: docker exec saltstack_master salt --versions
+
+      - name: Test image calling healthcheck
+        run: docker exec saltstack_master /usr/local/sbin/healthcheck
+
+      - name: Cleanup
+        run: |
+          docker stop saltstack_master registry
+          docker image rm ${IMAGE_NAME}