feat: Add changelog.yml for changelog generation

.github/workflows/changelog.yml

@@ -0,0 +1,41 @@
+name: Generate changelog
+
+on:
+  push:
+    branches:
+      - main
+      - master
+  pull_request:
+    branches:
+      - main
+      - master
+
+jobs:
+  generate-changelog:
+    name: Generate changelog
+    runs-on: ubuntu-20.04
+    outputs:
+      release_body: ${{ steps.release.outputs.release_body }}
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v2
+        with:
+          fetch-depth: 0
+      - name: Generate a changelog
+        uses: orhun/git-cliff-action@v1
+        id: git-cliff
+        with:
+          config: config/cliff.toml
+          args: -vv --latest --strip header
+        env:
+          OUTPUT: CHANGES.md
+      - name: Set the release body
+        id: release
+        shell: bash
+        run: |
+          r=$(cat ${{ steps.git-cliff.outputs.changelog }})
+          r="$(printf "$r" | tail -n +3)"
+          r="${r//'%'/'%25'}"
+          r="${r//$'\n'/'%0A'}"
+          r="${r//$'\r'/'%0D'}"
+          echo "::set-output name=release_body::$r"