ProPlot author here: Due to my day job as a graduate student, certain feature additions may be delayed to the summer of 2020. In the meantime, if you are interested in contributing to ProPlot, please see the contribution guide. Any amount of help is welcome!
Pass all arguments to pcolormesh then apply
settings that are suitable for heatmaps: no gridlines, no minor ticks,
and major ticks at the center of each grid box.