chore: update jsdoc.js (#274)

Author: summer-ji-eng

packages/google-cloud-asset/.jsdoc.js

@@ -36,11 +36,14 @@ module.exports = {
     includePattern: '\\.js$'
   },
   templates: {
-    copyright: 'Copyright 2018 Google, LLC.',
+    copyright: 'Copyright 2019 Google, LLC.',
     includeDate: false,
     sourceFiles: false,
     systemName: '@google-cloud/asset',
-    theme: 'lumen'
+    theme: 'lumen',
+    default: {
+      "outputSourceFiles": false
+    }
   },
   markdown: {
     idInHeadings: true