Remove "Linux - Travis CI" from docs (#4374)

Author: cac03

docs/supported_docker_environment/index.md

@@ -5,7 +5,6 @@
 | Host Operating System / Environment | Minimum recommended docker versions | Known issues / tips                                                                                                                                                                                                                                                                                                                                                |
 |-------------------------------------|-----------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
 | Linux - general                     | Docker v17.09              |                                                                                                                                                                                                                                                                                                                                                                    |
-| Linux - Travis CI                   | Docker v17.09              | See [example .travis.yml](https://raw.githubusercontent.com/testcontainers/testcontainers-java/master/.travis.yml) for baseline Travis CI configuration                                                                                                                                                                                                                                                                                     |
 | Linux - CircleCI (LXC driver)      | Docker v17.09               | The `exec` feature is not compatible with CircleCI. See CircleCI configuration [example](./continuous_integration/circle_ci.md)                                                                                                                                                                                                                                   |
 | Linux - within a Docker container            | Docker v17.09              | See [Running inside Docker](continuous_integration/dind_patterns.md) for Docker-in-Docker and Docker wormhole patterns                                                                                                                                                                                                                              |
 | Mac OS X - Docker Toolbox           | Docker Machine v0.8.0  |                                                                                                                                                                                                                                                                                                                                                                    |