Support contextmenu (for enabling right click events)

[jejay]

As far as I have understood, Mapbox does not fire a click event when a right click occurs. Instead it fires a contextmenu event. See mapbox/mapbox-gl-js#1416

My Problem now is, that the contextmenu event seems to be not supported by react-map-gl. So I cant listen to right click events.

I suggest a onContextmenu-prop on the InteractiveMap that consumes a callback.

[wuweiweiwu]

React provides a synthetic event wrapper for onContextMenu

So it'd be relatively straightforward to add a prop to mapbox that is passed into / or bound to the internal dom ref

[Pessimistress]

Added in 3.2.9