Upgrade to mapbox-gl 0.21.0

[mithrandi]

Currently, the dependency is on mapbox-gl^0.18.0; unfortunately, there are some problematic transitive dependencies of this version, resulting in a UNMET PEER DEPENDENCY browserify@>= 5 problem (which causes npm shrinkwrap to fail) as well as a deprecation warning from mapbox-gl-js-supported which has been renamed to mapbox-gl-supported.

Would it be possible to update the mapbox-gl version?

[etpinard]

Thanks for the headsup!

I tried bumping the mapbox-gl version but it made one our image test fail. Not sure if it's a new bug in mapbox-gl or a wrong implementation of their API on our part.

Further investigation is needed. Hopefully for before releasing plotly.js v1.16.0.

[etpinard]

Quick update: upgrading mapbox-gl will be a little trickier than I thought. The latest version removed mapboxgl.GeoJSONSource() and a few more methods that we're currently using. I'm still hoping to have mapbox-gl 0.22.x in plotly.js 1.17.0

[etpinard]

Progress on the bump-mapbox branch.

Waiting for a response to mapbox/mapbox-gl-js#3032 before continuing.