change OSV-scanner for pull_request as recommended (#615)

Signed-off-by: Fedor Partanskiy <[email protected]>

Author: pfi79

.github/workflows/vulnerability-scan.yml

@@ -21,4 +21,8 @@ permissions:
 
 jobs:
   scan-scheduled:
+    if: ${{ github.event_name == 'push' || github.event_name == 'schedule' }}
     uses: "google/osv-scanner-action/.github/workflows/[email protected]"
+  scan-pr:
+    if: ${{ github.event_name == 'pull_request' || github.event_name == 'merge_group' }}
+    uses: "google/osv-scanner-action/.github/workflows/[email protected]"