chore(package): update file-exists to version 5.0.1 (#2725)

package.json

@@ -80,7 +80,7 @@
     "clang-format": "1.1.0",
     "del": "~3.0.0",
     "eslint-plugin-angular": "~3.1.1",
-    "file-exists": "5.0.0",
+    "file-exists": "5.0.1",
     "google-closure-compiler": "~20171203.0.0",
     "google-closure-library": "~20171203.0.0",
     "gulp": "~3.9.1",