Support for tweepy >= 4.0.0

[fabaff]

tweepy-4.x was released a while back. Unfortunately is updating not as simple as bumping the dependency.

ImportError while loading conftest '/build/source/test/conftest.py'.
test/conftest.py:10: in <module>
    from ioccheck.iocs import IP, Hash
ioccheck/iocs/__init__.py:5: in <module>
    from .ioc import IOC, IOCReport  # isort:skip
ioccheck/iocs/ioc.py:13: in <module>
    from ioccheck.services import (MalwareBazaar, Service, Shodan, Twitter,
ioccheck/services/__init__.py:8: in <module>
    from .twitter import Twitter  # isort:skip
ioccheck/services/twitter.py:11: in <module>
    class Twitter(Service):  # pylint: disable=too-few-public-methods
ioccheck/services/twitter.py:28: in Twitter
    auth_errors = [tweepy.error.TweepError]
E   AttributeError: module 'tweepy' has no attribute 'error'