Update check.yml

.github/workflows/check.yml

@@ -3,6 +3,8 @@ on:
   workflow_dispatch:
   pull_request:
     types: [opened, synchronize, reopened, edited]
+    branches:
+      - master
 concurrency:
   group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.ref }}
   cancel-in-progress: true