Move browsers to cross-tool config

Created by: ai

Hi. I moved browsers from Autoprefixer’s inner option to browserslist in package.json.

Reason

• Autoprefixer team recommends only package.browserslist as a way to set target browsers.
• package.browserslist is used in many different tools. It is used by autoprefixer, stylelint-no-unsupported-browser-features, eslint-plugin-compat, postcss-cssnext, postcss-preset-env, postcss-normalize. The most important, this config will be used in next babel-preset-env 7.0.
• It is used by autoprefixer-info CLI tool. This CLI tool is part of autoprefixer package, but didn’t work correctly without Browserslist config.
• This config is useful not only for tools. The new developer will have the single place to check target browsers in a new project.
• CSS-Tricks agree that Browserslist config is really good idea.

Test

1. Create a new project.
2. Check project’s package.json for browserslist key.