Feature request: support `Enum`s in `inputMenu` and `inputChoice`

[AlexWaygood]

If I'm presenting a user with a list of choices, this works really nicely:

from pyinputplus import inputMenu

CHOICES = ('Go left', 'Go right')

inputMenu(choices=CHOICES, prompt='Pick a direction')

It would be really nice, however, to do this instead, which isn't supported:

from enum import Enum
from pyinputplus import inputMenu


class Choices(str, Enum):
    one = 'Go left'
    two = 'Go right'


inputMenu(choices=Choices, prompt='Pick a direction')

Enum classes are iterable, so will pass an isinstance(<enum_cls>, collections.abc.Iterable) test. But they're not, strictly speaking, sequences, which means this line raises an error if I try to feed in an Enum of choices.

Would it be possible to support Enums in inputMenu and inputChoices? I'd be happy to submit a PR if it would be helpful, but I don't know whether changing the validation function in pysimplevalidate would have unintended consequences.