Does `add_major_minor_ticks` support `GeoAxes`?

[kafitzgerald]

Clarify if add_major_minor_ticks has support for Cartopy GeoAxes and if not, considering adding it (if it's not a major lift).

The docstring leads me to think it might (though I'm not sure why it says cartopy.mpl.geoaxes.GeoAxesSubplot), but the function doesn't seem to have any projection handling.

[kafitzgerald]

I still have yet to verify this, but I strongly suspect it doesn't.

And the functions to set ticks in Cartopy have some limitations with respect to coordinate systems / transformations. See here: https://cartopy.readthedocs.io/stable/reference/generated/cartopy.mpl.geoaxes.GeoAxes.html#cartopy.mpl.geoaxes.GeoAxes.set_xticks