feat: Change 'npm audit' failure behaviour

The audit fails only if the results include a vulnerability with a level of
at least 'high' in scheduled pipelines.

src/common.ts

@@ -752,7 +752,7 @@ export function getRules(configuration: Configuration): Rules {
         'schedules',
       ],
       script: [
-        'npm audit',
+        'npm audit --audit-level=high',
       ],
       stage: 'audit',
     },