Bump version to 3.1.0 for release.

Author: EvieePy

twitchio/__init__.py

@@ -26,7 +26,7 @@
 __author__ = "PythonistaGuild"
 __license__ = "MIT"
 __copyright__ = "Copyright 2017-Present (c) TwitchIO, PythonistaGuild"
-__version__ = "3.1.0b"
+__version__ = "3.1.0"
 
 from . import (  # noqa: F401
     authentication as authentication,