add prodigy deps

[crapthings]

add missing optimizer deps for beginner

[linoytsaban]

hey @crapthings, we try to keep the dependencies as minimal as possible, and since training with prodigy is optional (and the default is AdamW) we kept it out of the requirements and raise this error:

diffusers/examples/dreambooth/train_dreambooth_flux.py

Lines 1304 to 1308 in b5c2050

	if args.optimizer.lower() == "prodigy":
	try:
	import prodigyopt
	except ImportError:
	raise ImportError("To use Prodigy, please install the prodigyopt library: `pip install prodigyopt`")

however I see how this may lead to some frustration so we perhaps could add a note to the README to make sure to install prodigyopt if you wish to use prodigy.
cc @sayakpaul @asomoza

[sayakpaul]

Yeah having installation instructions is the best we can do IMO.