ci: Add scheduled workflow to update changelog

Signed-off-by: Yuan Tang <terrytangyuan@gmail.com>

.github/workflows/changelog.yml

@@ -0,0 +1,28 @@
+name: Update Changelog
+
+on:
+  schedule:
+    - cron: "0 0 * * 6"
+
+permissions:
+  contents: read
+
+jobs:
+  generate_changelog:
+    name: Generate changelog
+    permissions:
+      contents: write  # for peter-evans/create-pull-request to create branch
+      pull-requests: write  # for peter-evans/create-pull-request to create a PR
+    runs-on: ubuntu-24.04
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          ref: main
+          fetch-depth: 0
+      - run: python ./scripts/gen-changelog.py
+      - uses: peter-evans/create-pull-request@v6
+        with:
+          title: 'docs: update CHANGELOG.md for ${{ github.ref_name }}'
+          commit-message: 'docs: update CHANGELOG.md for ${{ github.ref_name }}'
+          branch: create-pull-request/changelog
+          signoff: true