Update .travis.yml

[JafarAbdi]

Description

Please explain the changes you made, including a reference to the related issue if applicable

Checklist

• [ ] Required by CI: Code is auto formatted using clang-format
• [ ] Extended the tutorials / documentation, if necessary reference
• [ ] Include a screenshot if changing a GUI
• [ ] Document API changes relevant to the user in the moveit/MIGRATION.md notes
• [ ] Created tests, which fail without this PR reference
• [ ] Decide if this should be cherry-picked to other current ROS branches
• [ ] While waiting for someone to review your request, please consider reviewing another open pull request to support the maintainers