Switch from babel-preset-es2015 to babel-preset-env

[OskarPersson]

See http://babeljs.io/env for more information

[wildlyinaccurate]

Hey, thanks for submitting this! My main concern with using the env preset is that it would require dropping support for older browsers. What would be the benefit of using the env preset over es2015?

[OskarPersson]

From my understanding, using env without any configuration should be the same as using es2015:

Without any configuration options, @babel/preset-env behaves exactly the same as @babel/preset-es2015, @babel/preset-es2016 and @babel/preset-es2017 together (or the deprecated babel-preset-latest).

https://github.com/babel/babel/tree/master/packages/babel-preset-env#babelpreset-env----