Add support for defining additionalLibraries as a regexp expression

[pkuczynski]

This PR brings new feature (from README.md)

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Regular expressions

If you are using Babel 7 or newer and your config is stored in babel.config.js, you can also use a regular expression to describe modules, which should be removed.

This would be particularly useful when using custom prop types validators, implemented as part of your own source code. For example

 import CustomPropTypes from '../../prop-types/my-own-validator'
 import OtherCustomPropTypes from '../../prop-types/my-other-validator'

would be removed with the following setting

 additionalLibraries: [/\/prop-types\/.*$/]

If you use an index file

 import CustomPropTypes from '../../prop-types'

you could set it up as

 additionalLibraries: [/\/prop-types$/]

[pkuczynski]

Do you want me to add some tests before you merge it in?

[oliviertassinari]

@pkuczynski One simple test would be great :)

[pkuczynski]

Sure! The only reason why I haven’t done this so far was that I wasn’t really sure if you would accept this contribution and like the idea.

I will add a test tomorrow, when I get back to my laptop.

Any chance this would be merged and released anytime soon?

[oliviertassinari]

Yes, we can release quickly after.

[pkuczynski]

Tests added. I change path-exists to globby, as it makes it a bit easier to require files by the pattern. I hope you don't mind?

[pkuczynski]

Looking forward to hearing some feedback for you and get this released...

[oliviertassinari]

@pkuczynski Thank you

[pkuczynski]

Thanks! :)