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

Author: greenkeeper[bot]

package.json

@@ -21,7 +21,7 @@
     "debug": "^4.0.0",
     "dir-glob": "^2.0.0",
     "execa": "^1.0.0",
-    "fs-extra": "^7.0.0",
+    "fs-extra": "^8.0.0",
     "globby": "^9.0.0",
     "lodash": "^4.17.4",
     "micromatch": "^4.0.0",