Remove pickling when saving FunctionalCorrector

[jmbhughes]

Pickles are inherently unsafe and can have portability issues. We should use a different format. I'm unsure what is a better alternative off-hand.

regularizepsf/regularizepsf/corrector.py

Lines 165 to 172 in ded2c7b

	def save(self, path: str) -> None:
	with open(path, "wb") as f:
	dill.dump(self, f)
	@classmethod
	def load(cls, path: str) -> FunctionalCorrector:
	with open(path, "rb") as f:
	return dill.load(f)

[jmbhughes]

In addition, they make ruff fail in our internal CI linting step.