[fix-reusable-workflow] Fixed reusable workflow for compatibility wit…

…h caller workflows. (#307)

.github/workflows/vulnerability-scan.yml

@@ -13,6 +13,18 @@ on:
         description: 'Tag to scan.'
         required: false
         default: '6.x'
+  workflow_call:
+    inputs:
+      summary:
+        description: 'Summary of the scheduled scan.'
+        required: false
+        default: 'Trivy CVE scan of published images.'
+        type: string
+      tag:
+        description: 'Tag to scan.'
+        required: false
+        default: '6.x'
+        type: string
 jobs:
   setup-matrix:
     runs-on: ubuntu-latest