ci: Travis: do not test with 3.5.0
ci: Travis: do not test with 3.5.0

This causes flaky test failures (crashes).

Closes https://github.com/pytest-dev/pytest/issues/5795.

Akasurde/pytest,nicoddemus/pytest,alfredodeza/pytest,nicoddemus/pytest,tomviner/pytest,markshao/pytest,RonnyPfannschmidt/pytest,tomviner/pytest,pytest-dev/pytest,The-Compiler/pytest,The-Compiler/pytest