Add support for "maxWidth" to the Popup Component

[WesWedding]

Is your feature request related to a problem? Please describe.
The MapboxGL's Popup has a maxWidth option that allows you to override the default '240px' max-width that gets set on the popup's DOM element. It would be more convenient to use this built-in API than to resort to things like sprinkling !important in your CSS.

Describe the solution you'd like
Add support for maxWidth so that the following is possible...

...
<Popup 
  latitude={0}
  longitude={0}
  maxWidth={'none'}>
    Content
</Popup>

[stepankuzmin]

Thanks, @WesWedding!