About apng_square_and_optimize.py

[g1186246]

Firstly, thank you for your script, but after I used your script I find a problem due to the image type
I used another user(or yours?) script(https://github.com/signalstickers/signalstickers-client) as reference created code for upload sticker automatically, but after update the sticker, the animated sticker will not play in ios,

I check the log over here signalapp/Signal-iOS#4611 , which said that the image type need to be without palette ,but I am not specialize in image, even I tried some way, but still doesn't work, is it possible to change the format?
@romainricard

[g1186246]

This is the file after converted by script which ios doesn't play anime

This is the file after converted by script and then converted by isparta which ios can play anime