Hey! thank you!
Do you mean literally only black and white with no greys, like a 1bit graphics? Then I don't think it is possible because there are many different shade of green and make it 2 colours would be a big amount of work (but if you find a way let me know, it would be interesting).
But if you mean to desaturate it to make it in shades of grey, no problem, you can fix the colours, saturation and contrast as you need. This is something you can do with many programs, what do you use?
Let me know if I answered your question or if you need anything else. If you want to write me an email you can find it in the txt with the asset files
Keep me updated, I'm curious :)