Fabric API – [1.20.1] Fabric API 0.87.0+1.20.1

– Bump version (modmuss50)
– Improve Indigo and FRAPI Test Mod (#3208) (PepperCode1)
– Make DFU error-tolerant to mod custom generator types (#3213) (qouteall)
– Make deprecated modules opt-out instead of opt-in (#3246) (modmuss, Juuz)
– Fix #3255 (#3257) (modmuss)