fix(package): update @babel/preset-env to version 7.7.4

Closes #251

Author: greenkeeper[bot]

package.json

@@ -54,7 +54,7 @@
     "@babel/core": "7.7.4",
     "@babel/plugin-syntax-dynamic-import": "7.7.4",
     "@babel/plugin-syntax-object-rest-spread": "7.7.4",
-    "@babel/preset-env": "7.6.2",
+    "@babel/preset-env": "7.7.4",
     "@babel/register": "7.6.2",
     "babel-loader": "8.0.6",
     "chalk": "2.4.2",