fix(package): update fs-extra to version 8.0.0

Author: greenkeeper[bot]

package.json

@@ -22,7 +22,7 @@
     "bottleneck": "^2.0.1",
     "debug": "^4.0.0",
     "dir-glob": "^2.0.0",
-    "fs-extra": "^7.0.0",
+    "fs-extra": "^8.0.0",
     "globby": "^9.0.0",
     "http-proxy-agent": "^2.1.0",
     "https-proxy-agent": "^2.2.1",