docs: add output (#12)

Output
ING-6578

.github/workflows/heinrichreimeraction-github-changelog-generator.yml

@@ -1,6 +1,7 @@
- # https://github.com/actions/create-release#example-workflow---create-a-release
+# https://github.com/marketplace/actions/generate-changelog
+
+name: 'Create Release Heinrichreimer'
 
-name: 'Create Release'
 on:
   push:
     # Sequence of patterns matched against refs/tags
@@ -12,5 +13,8 @@ jobs:
     steps:
       - name: "✏️ Generate release changelog"
         uses: heinrichreimer/[email protected]
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }} # This token is provided by Actions, you do not need to create your own token
         with:
-          token: ${{ secrets.GITHUB_TOKEN }} 
+          token: ${{ secrets.GITHUB_TOKEN }} 
+          output: CHANGELOG.md