add changelog generator pipeline

Author: OliverDrechsler

.github/changelog.yml

@@ -0,0 +1,16 @@
+name: Changelog Generator
+on:
+  pull_request:
+    branches:
+      - master
+    types: [opened, reopened, synchronize]
+
+jobs:
+  changelog:
+    name: Chanegelog Generator
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - uses: etcdigital/pull-request-changelog@master
+        with:
+          token: ${{ secrets.GITHUB_TOKEN }}