chore(ci): add release automerge workflow (#111)

Author: skyrpex

.github/workflows/release-automerge.yml

@@ -0,0 +1,30 @@
+name: Release Automerge
+
+on:
+  schedule:
+    - cron: '0 9 * * 1'
+  workflow_dispatch:
+
+permissions:
+  contents: write
+  pull-requests: write
+
+jobs:
+  merge:
+    name: Merge Release PR
+    runs-on: ubuntu-latest
+    steps:
+      - name: Find and merge autorelease PR
+        env:
+          GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+          REPO: ${{ github.repository }}
+        run: |
+          PR=$(gh pr list --repo "$REPO" --label "autorelease: pending" --state open --json number,url --jq '.[0]')
+          if [ -z "$PR" ] || [ "$PR" = "null" ]; then
+            echo "No autorelease PR found, nothing to do."
+            exit 0
+          fi
+          PR_NUMBER=$(echo "$PR" | jq -r '.number')
+          PR_URL=$(echo "$PR" | jq -r '.url')
+          echo "Merging PR #$PR_NUMBER: $PR_URL"
+          gh pr merge "$PR_NUMBER" --repo "$REPO" --merge