chore(package): update cross-env to version 7.0.1

Closes #52

Author: greenkeeper[bot]

package.json

@@ -89,7 +89,7 @@
     "babel-preset-stage-2": "^6.18.0",
     "babel-runtime": "^6.26.0",
     "coveralls": "^3.0.0",
-    "cross-env": "^5.1.0",
+    "cross-env": "^7.0.1",
     "hapi": "^17.2.3",
     "jest": "^22.0.0",
     "nodemon": "^1.9.0",