ci: Travis: skip coverage with cron runs
ci: Travis: skip coverage with cron runs

The current commit on features has 50+ uploads already:
https://codecov.io/gh/pytest-dev/pytest/commit/c7bbb2a78873a63b9df9df08f8dc77cde30debd3/build

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