Support release notes generation (#1150)

Add github actions to automatically populate release notes on tag push.
This should make it easier to show what new functionality/improvements
have been added by populating the release page based on PRs and issues.

.github/workflows/docker-image.yml

@@ -1,11 +1,11 @@
-name: ci
+name: docker-image
 
 on:
   push:
     branches:
       - '**'
     tags:
-      - 'v*'
+      - '*.*.*'
   pull_request:
 
 jobs:
@@ -34,9 +34,9 @@ jobs:
             VERSION=pr-${{ github.event.number }}
           fi
           TAGS="${DOCKER_IMAGE}:${VERSION}"
-          if [[ $VERSION =~ ^v[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}$ ]]; then
+          if [[ $VERSION =~ ^[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}$ ]]; then
             MINOR=${VERSION%.*}
-            MAJOR=${MINOR%.*}
+            MAJOR=v${MINOR%.*}
             TAGS="$TAGS,${DOCKER_IMAGE}:${MINOR},${DOCKER_IMAGE}:${MAJOR},${DOCKER_IMAGE}:latest"
           elif [ "${{ github.event_name }}" = "push" ]; then
             TAGS="$TAGS,${DOCKER_IMAGE}:sha-${GITHUB_SHA::8}"

.github/workflows/release.yml

@@ -0,0 +1,41 @@
+name: release
+
+on:
+  push:
+    tags:
+      - '*.*.*'
+
+jobs:
+  release:
+    name: Create Release
+    runs-on: ubuntu-latest
+    steps:
+      -
+        name: Checkout code
+        uses: actions/checkout@v2
+      -
+        name: Prepare
+        id: prep
+        run: |
+          LAST_TAG=$(git describe --tags --abbrev=0 HEAD~1 2>/dev/null || true)
+          echo ::set-output name=previous_version::${LAST_TAG}
+      -
+        name: Changelog Generation
+        uses: CharMixer/auto-changelog-action@v1.1
+        with:
+          token: ${{ secrets.GITHUB_TOKEN }}
+          since_tag: ${{ steps.prep.outputs.previous_version }}
+          output: release_notes.md
+      -
+        name: Create Release
+        id: create_release
+        uses: actions/create-release@v1
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        with:
+          tag_name: ${{ github.ref }}
+          release_name: Release ${{ github.ref }}
+          body_path: release_notes.md
+          draft: false
+          prerelease: false
+