ci: cancel in-progress release-plz PRs

Author: Boshen

.github/workflows/release-plz.yml

@@ -8,6 +8,10 @@ on:
     branches:
       - main
 
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
 jobs:
   release-plz:
     name: Release-plz