Update secrets-scanner.yml workflow

Author: tinyfish-github-terraform[bot]

.github/workflows/secrets-scanner.yml

@@ -6,6 +6,9 @@
 name: Leaked Secrets Scan
 on: # yamllint disable-line rule:truthy
   pull_request:
+  merge_group:
+    branches: [main]
+
 jobs:
   TruffleHog:
     runs-on: ubuntu-latest