ci: apply concurrency limit for github workflows (#6243)

.github/workflows/server.yml

@@ -18,6 +18,10 @@ on:
   schedule:
     -  cron: '0 0 * * *'
 
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
 jobs:
   server:
     runs-on: ubuntu-latest