chore(deps): update dependency fs-extra to v8 (#1610)

Author: renovate[bot]

package.json

@@ -112,7 +112,7 @@
         "eslint-plugin-markdown": "^1.0.0",
         "eslint-plugin-vue": "^6.0.0",
         "fetch-jsonp": "^1.1.3",
-        "fs-extra": "^7.0.0",
+        "fs-extra": "^8.0.0",
         "glob": "^7.1.2",
         "gulp": "^4.0.1",
         "gulp-babel": "^7.0.0",