chore(package): update cross-env to version 6.0.2

Closes #42

Author: greenkeeper[bot]

package.json

@@ -47,7 +47,7 @@
     "babel-plugin-inline-import": "^2.0.6",
     "babel-preset-env": "^1.6.1",
     "cpy-cli": "^1.0.1",
-    "cross-env": "^5.1.3",
+    "cross-env": "^6.0.2",
     "del-cli": "^1.1.0",
     "eslint": "^4.13.1",
     "eslint-config-airbnb-base": "^12.1.0",