Add changelog for 0.19.0 release
Add changelog for 0.19.0 release

aaronxsu/raster-foundry,aaronxsu/raster-foundry,raster-foundry/raster-foundry,azavea/raster-foundry,raster-foundry/raster-foundry,aaronxsu/raster-foundry,azavea/raster-foundry,azavea/raster-foundry,azavea/raster-foundry,azavea/raster-foundry,raster-foundry/raster-foundry,aaronxsu/raster-foundry