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

Closes #356

Author: greenkeeper[bot]

package.json

@@ -64,7 +64,7 @@
     "circular-dependency-plugin": "^4.4.0",
     "compression-webpack-plugin": "^1.1.7",
     "copy-webpack-plugin": "^4.4.1",
-    "cross-env": "^5.1.3",
+    "cross-env": "^7.0.0",
     "css-loader": "^0.28.9",
     "enzyme": "^3.3.0",
     "enzyme-adapter-react-16": "^1.1.1",