Add changelog workflow (#2429)

Author: t-wright

.github/workflows/changelog.yml

@@ -0,0 +1,24 @@
+name: Public Changelog
+on:
+  workflow_dispatch:
+  release:
+    types: [published]
+
+jobs:
+  changelog:
+    name: Public Changelog
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+      pull-requests: read
+    steps:
+      - uses: actions/checkout@v4
+      - uses: Automattic/vip-actions/changelog@f083b1e1e0cd092ee5cafa6621d32a28c68bf7ee # trunk
+        with:
+          endpoint: ${{ vars.CHANGELOG_POST_ENDPOINT }}
+          endpoint-token: ${{ secrets.CHANGELOG_POST_TOKEN }}
+          repo-token: ${{ secrets.GITHUB_TOKEN }}
+          status: 'draft'
+          category-id: '26'
+          link-to-pr: true
+          source: 'last-release'