Merge pull request #38 from storybooks/add-babel/preset-env

feat: Add missing @babel/preset-env as dev dependency

Author: ndelangen

package.json

@@ -18,6 +18,7 @@
     "@babel/core": "^7.2.0",
     "@babel/plugin-proposal-class-properties": "^7.2.0",
     "@babel/plugin-proposal-export-default-from": "^7.2.0",
+    "@babel/preset-env": "^7.2.0",
     "@babel/preset-flow": "^7.0.0",
     "@babel/preset-react": "^7.0.0",
     "@storybook/addon-actions": "^4.1.1",