Support browserslist about babel-preset-vue-app HOT 1 OPEN

After tweaking some code for a while I came up with this idea.

babel-preset-env has this option: ignoreBrowserslistConfig.
So, we can make use of it: when it is specified (default) we can fallback to { ie: 9, uglify: true }.
But, when it is set to false - then we just pass undefined to the options here: https://github.com/vuejs/babel-preset-vue-app/blob/master/src/index.js#L21

Something like this:

[require('babel-preset-env').default, {
  useBuiltIns,
  targets: ignoreBrowserslistConfig ? targets : undefined,
  modules: false
}],

@egoist what do you think? I can create a PR if that's fine.

from babel-preset-vue-app.