update actions ci config

.github/workflows/pr-changelog-check.yml

@@ -1,12 +1,14 @@
 name: Pull request changelog check
-on: [pull_request]
+on:
+  pull_request:
+    types: [opened, labeled, unlabeled, synchronize]
 jobs:
   build:
+    if: ${{ !(contains(github.event.pull_request.labels.*.name, 'changelog-not-required')) }}
     name: Run changelog check
     runs-on: ubuntu-latest
     steps:
       - name: Check out the code
         uses: actions/checkout@v2
       - name: Changelog check
-        if: ${{ !(contains(github.event.pull_request.labels.*.name, 'changelog-not-required'))}}
         run: ./scripts/changelog-check.sh