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

Closes #24

Author: greenkeeper[bot]

package.json

@@ -55,7 +55,7 @@
     "babel-preset-env": "^1.6.1",
     "babel-preset-flow": "^6.23.0",
     "babel-runtime": "^6.26.0",
-    "cross-env": "^5.1.4",
+    "cross-env": "^7.0.1",
     "flow-bin": "^0.71.0",
     "jest": "^22.4.3",
     "kcd-scripts": "^0.37.0",