Remove leftover Travis CI references (#856)

Author: tvainika

docs/conf.py

@@ -150,9 +150,8 @@ def get_version(release):
     'description': 'Apache Kafka client for asyncio',
     'github_user': 'aio-libs',
     'github_repo': 'aiokafka',
-    'github_button': False,
+    'github_button': True,
     'github_banner': True,
-    'travis_button': True,
     'codecov_button': True,
     'note_bg': '#E5ECD1',
     'note_border': '#BFCF8C',

docs/index.rst

@@ -172,9 +172,6 @@ Please feel free to file an issue on `bug tracker
 <https://github.com/aio-libs/aiokafka/issues>`_ if you have found a bug
 or have some suggestion for library improvement.
 
-The library uses `Travis <https://travis-ci.com/aio-libs/aiokafka>`_ for
-Continious Integration.
-
 
 Authors and License
 -------------------