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

Closes #88

Author: greenkeeper[bot]

package.json

@@ -84,7 +84,7 @@
     "chai": "^4.2.0",
     "chalk": "^2.4.2",
     "copy-webpack-plugin": "^5.0.0",
-    "cross-env": "^5.2.0",
+    "cross-env": "^6.0.2",
     "css-loader": "2.1.1",
     "del": "^4.0.0",
     "devtron": "^1.4.0",