Upgrade fs-extra to v7.0.0

Fix #NONE

Author: Minggang Wang

package.json

@@ -38,14 +38,14 @@
     "debug": "^3.1.0",
     "deep-equal": "^1.0.1",
     "dot": "^1.1.2",
-    "fs-extra": "^6.0.1",
-    "mz": "^2.6.0",
+    "fs-extra": "^7.0.0",
     "mkdirp": "^0.5.1",
+    "mz": "^2.6.0",
+    "nan": "^2.8.0",
     "ref": "^1.3.4",
-    "ref-struct": "^1.1.0",
     "ref-array": "^1.2.0",
-    "walk": "^2.3.9",
-    "nan": "^2.8.0"
+    "ref-struct": "^1.1.0",
+    "walk": "^2.3.9"
   },
   "engines": {
     "node": ">= 6.10.0"