chore: copy most recent changelog entry when creating a release

.github/workflows/cd.yml

@@ -68,13 +68,22 @@ jobs:
                   REDIS_URL: 'redis://localhost'
                   NODE_AUTH_TOKEN: ${{ secrets.NPM_TOKEN }}
 
+            - name: Set LAST_CHANGELOG_ENTRY
+              run: |
+                # read from the first until the second header in the changelog file
+                # this assumes the formatting of the file
+                # and that this workflow is always running for the most recent entry in the file 
+                LAST_CHANGELOG_ENTRY=$(awk '/^## /{if (flag) exit; flag=1} flag && /^##$/{exit} flag' CHANGELOG.md)
+                echo "LAST_CHANGELOG_ENTRY=$LAST_CHANGELOG_ENTRY" >> $GITHUB_ENV
+
             - name: Create GitHub release
               uses: actions/create-release@v1
               env:
                   GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
               with:
                   tag_name: v${{ env.COMMITTED_VERSION }}
                   release_name: ${{ env.COMMITTED_VERSION }}
+                  body: ${{ env.LAST_CHANGELOG_ENTRY || 'see CHANGELOG.md' }}
 
     create-pull-request:
         name: Create main repo PR with new posthog-js version