message: Update Webpack guide to use babel preset-env
diff: @@ -244,7 +244,7 @@ ES modules to CommonJS modules only in the `test` environment.
  ```json
  // .babelrc
  {
  - "presets": [["es2015", {"modules": false}]],
  + "presets": [["env", {"modules": false}]],
  "env": {
  "test": {
  @@ -263,7 +263,7 @@ need to enable the `dynamic-import-node` plugin.
  ```json
  // .babelrc
  {
  - "presets": [["es2015", {"modules": false}]],
  + "presets": [["env", {"modules": false}]],
  "plugins": ["syntax-dynamic-import"],
  