fix #572, move cross-env to devDependencies

package.json

@@ -7,7 +7,6 @@
     "axios": "^0.17.1",
     "babel-polyfill": "^6.23.0",
     "classnames": "^2.2.5",
-    "cross-env": "^5.0.5",
     "d3-shape": "^1.2.0",
     "draftjs-to-markdown": "^0.5.0",
     "dva": "2.1.0",
@@ -47,6 +46,7 @@
     "babel-plugin-transform-runtime": "^6.9.0",
     "babel-runtime": "^6.9.2",
     "copy-webpack-plugin": "^4.0.1",
+    "cross-env": "^5.0.5",
     "draftjs-to-html": "^0.8.1",
     "dva-model-extend": "^0.1.1",
     "eslint": "^4.1.1",