Bump travis from 1.8.10 to 1.8.11

Bumps [travis](https://github.com/travis-ci/travis.rb) from 1.8.10 to 1.8.11.
- [Release notes](https://github.com/travis-ci/travis.rb/releases)
- [Commits](https://github.com/travis-ci/travis.rb/commits)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

Author: dependabot-preview[bot]

Gemfile.lock

@@ -393,7 +393,7 @@ GEM
     thor (1.0.1)
     thread_safe (0.3.6)
     tilt (2.0.10)
-    travis (1.8.10)
+    travis (1.8.11)
       backports
       faraday (~> 0.9)
       faraday_middleware (~> 0.9, >= 0.9.1)