chore(package): update cross-env to version 7.0.0

Closes #36

Author: greenkeeper[bot]

package.json

@@ -58,7 +58,7 @@
     "babel-core": "^7.0.0-bridge.0",
     "babel-jest": "^23.6.0",
     "babel-loader": "^8.0.0-beta.4",
-    "cross-env": "^5.2.0",
+    "cross-env": "^7.0.0",
     "css-loader": "^2.0.1",
     "enzyme": "^3.7.0",
     "enzyme-adapter-react-16": "^1.7.0",