Feature: Allow options for verification and requirement of azp

[redbmk]

Could we add an option to verify azp (Authorized party - the party to which the ID Token was issued)? For example:

jwt.decode(
  token,
  key,
  azp="asdf1234",
  options: {"require_azp": True},
)

[redbmk]

Current workaround would simply be something like this:

claims = jwt.decode(...)
if "azp" not in claims:
    raise JWTError("Expected azp to be in claims")
elif calims["azp"] != expected_azp
    raise JWTError("Invalid authorized party")