Bump version

Author: lgrahl

threema/gateway/__init__.py

@@ -35,7 +35,7 @@
 
 __author__ = 'Lennart Grahl <lennart.grahl@threema.ch>'
 __status__ = 'Production'
-__version__ = '2.1.5'
+__version__ = '2.1.6'
 __all__ = (
     'feature_level',
     'ReceptionCapability',