Update to use semver for images

.github/workflows/docker-ci.yml

@@ -0,0 +1,49 @@
+name: docker-ci
+
+on:
+  push:
+    branches:
+      - 'master'
+    tags:
+      - 'v*'
+  pull_request:
+
+jobs:
+  docker:
+    runs-on: ubuntu-latest
+    steps:
+      -
+        name: Checkout
+        uses: actions/checkout@v2
+      -
+        name: Docker meta
+        id: docker_meta
+        uses: crazy-max/ghaction-docker-meta@v1
+        with:
+          images: dbomproject/chainsource-gateway
+          tag-semver: |
+            {{version}}
+            {{major}}.{{minor}}
+      -
+        name: Set up QEMU
+        uses: docker/setup-qemu-action@v1
+      -
+        name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v1
+      -
+        name: Login to DockerHub
+        if: github.event_name != 'pull_request'
+        uses: docker/login-action@v1 
+        with:
+          username: ${{ secrets.DOCKERHUB_USERNAME }}
+          password: ${{ secrets.DOCKERHUB_TOKEN }}
+      -
+        name: Build and push
+        uses: docker/build-push-action@v2
+        with:
+          context: .
+          file: ./Dockerfile
+          platforms: linux/amd64,linux/386
+          push: ${{ github.event_name != 'pull_request' }}
+          tags: ${{ steps.docker_meta.outputs.tags }}
+          labels: ${{ steps.docker_meta.outputs.labels }}