Add "update-changelog.yml" workflow

Author: Lukasss93

.github/workflows/update-changelog.yml

@@ -0,0 +1,28 @@
+name: "Update Changelog"
+
+on:
+    release:
+        types: [ released ]
+
+jobs:
+    update:
+        runs-on: ubuntu-latest
+
+        steps:
+            -   name: Checkout code
+                uses: actions/checkout@v2
+                with:
+                    ref: master
+
+            -   name: Update Changelog
+                uses: stefanzweifel/changelog-updater-action@v1
+                with:
+                    latest-version: ${{ github.event.release.tag_name }}
+                    release-notes: ${{ github.event.release.body }}
+
+            -   name: Commit updated CHANGELOG
+                uses: stefanzweifel/git-auto-commit-action@v4
+                with:
+                    branch: master
+                    commit_message: Update CHANGELOG
+                    file_pattern: CHANGELOG.md