v2.15.7

• Fix a crash when inferring a typing.TypeVar call.

  Closes pylint-dev/pylint#8802

• Infer user-defined enum classes by checking if the class is a subtype of enum.Enum.

  Closes pylint-dev/pylint#8897

• Fix inference of functions with @functools.lru_cache decorators without
  parentheses.

  Closes pylint-dev/pylint#8868

• Make sys.argv uninferable because it never is. (It's impossible to infer
  the value it will have outside of static analysis where it's our own value.)

  Refs pylint-dev/pylint#7710