fx-extra upgrade

package.json

@@ -52,7 +52,7 @@
     "babel-preset-es2016": "^6.16.0",
     "babel-preset-react": "^6.0.0",
     "escape-string-regexp": "^1.0.3",
-    "fs-extra": "^3.0.0",
+    "fs-extra": "^4.0.0",
     "glob": "^7.1.1",
     "happypack": "^3.1.0",
     "html-webpack-plugin": "^2.17.0",

yarn.lock

@@ -1772,12 +1772,12 @@ fs-access@^1.0.0:
   dependencies:
     null-check "^1.0.0"
 
-fs-extra@^3.0.0:
-  version "3.0.1"
-  resolved "https://registry.yarnpkg.com/fs-extra/-/fs-extra-3.0.1.tgz#3794f378c58b342ea7dbbb23095109c4b3b62291"
+fs-extra@^4.0.0:
+  version "4.0.2"
+  resolved "https://registry.yarnpkg.com/fs-extra/-/fs-extra-4.0.2.tgz#f91704c53d1b461f893452b0c307d9997647ab6b"
   dependencies:
     graceful-fs "^4.1.2"
-    jsonfile "^3.0.0"
+    jsonfile "^4.0.0"
     universalify "^0.1.0"
 
 fs.realpath@^1.0.0:
@@ -2354,9 +2354,9 @@ json5@^0.5.0, json5@^0.5.1:
   version "0.5.1"
   resolved "https://registry.yarnpkg.com/json5/-/json5-0.5.1.tgz#1eade7acc012034ad84e2396767ead9fa5495821"
 
-jsonfile@^3.0.0:
-  version "3.0.1"
-  resolved "https://registry.yarnpkg.com/jsonfile/-/jsonfile-3.0.1.tgz#a5ecc6f65f53f662c4415c7675a0331d0992ec66"
+jsonfile@^4.0.0:
+  version "4.0.0"
+  resolved "https://registry.yarnpkg.com/jsonfile/-/jsonfile-4.0.0.tgz#8771aae0799b64076b76640fca058f9c10e33ecb"
   optionalDependencies:
     graceful-fs "^4.1.6"