Merge pull request #8145 from openlayers/greenkeeper/fs-extra-6.0.0

Update fs-extra to the latest version 🚀

package.json

@@ -54,7 +54,7 @@
     "eslint-config-openlayers": "^9.0.0",
     "expect.js": "0.3.1",
     "front-matter": "^2.1.2",
-    "fs-extra": "^5.0.0",
+    "fs-extra": "^6.0.0",
     "google-closure-compiler": "20180402.0.0",
     "handlebars": "4.0.11",
     "html-webpack-plugin": "^3.0.1",