Add check workflow events related checks (#1128) (#1129)

Signed-off-by: Peter Zhu <[email protected]>
(cherry picked from commit 2365ffd)

Co-authored-by: Peter Zhu <[email protected]>

Author: opensearch-trigger-bot[bot]

.github/workflows/check-workflow-events.yml

@@ -0,0 +1,30 @@
+name: Check Workflow Events
+on:
+  pull_request:
+    paths:
+      - '.github/workflows/**'
+
+jobs:
+  check-workflow-events:
+    runs-on: ubuntu-latest
+    name: Check Workflow Events
+    steps:
+      - uses: actions/checkout@v4
+      - name: Check Workflow Events
+        working-directory: .github/workflows
+        run: |
+          set +e
+          EVENT_COUNT=0
+          for file_found in `ls | grep .ym`; do
+              yq -r e '.on | keys | .[0]' $file_found | grep -q pull_request_target
+              EVENT_FOUND=$?
+
+              if [ "$EVENT_FOUND" = 0 ] && [ "$file_found" != "backport.yml" ] && [ "$file_found" != "copy-linked-issue-labels.yml" ]; then
+                EVENT_COUNT=$(( EVENT_COUNT+1 ))
+                echo "'$file_found' workflow file contains 'pull_request_target' event, please remove!"
+              fi
+          done
+
+          if [ "$EVENT_COUNT" != 0 ]; then
+              exit 1
+          fi