Changing values on a wind rose legend

I have downloaded the wind_rose function and have produced the plot I wanted, but the legend has set values as 0-0.1 (dark blue), 0.1-0.2 (lighter blue) etc going up the colour scale. However, I want to change how the legend sees the data. For example I'd like 0-0.5 (dark blue), 0.5-1 (lighter blue) etc. Does this get changed in the wind_rose function or the script that I write? and what do I need to write to get this result. Any help would be useful, thanks.