fix(package): update fs-extra to version 8.0.1 (#350)

Closes #349

Author: s0ph1e

package.json

@@ -37,7 +37,7 @@
     "cheerio": "0.22.0",
     "css-url-parser": "^1.0.0",
     "debug": "^4.0.1",
-    "fs-extra": "^7.0.0",
+    "fs-extra": "^8.0.1",
     "he": "^1.1.0",
     "lodash": "^4.17.5",
     "normalize-url": "^4.0.0",