skip_cleanup deperecated

[mymindstorm]

My builds have a deprecation warning for skip_cleanup, but the documentation still uses skip_cleanup.

https://docs.travis-ci.com/user/deployment/google-app-engine#sts=Skipping%20Cleanup
https://docs.travis-ci.com/user/deployment/#uploading-files-and-skip_cleanup

[stale]

Thanks for contributing to this issue. As it has been 90 days since the last activity, we are automatically closing the issue. This is often because the request was already solved in some way and it just wasn't updated or it's no longer applicable. If that's not the case, please do feel free to either reopen this issue or open a new one. We'll gladly take a look again! You can read more here: https://blog.travis-ci.com/2018-03-09-closing-old-issues

[mymindstorm]

Please re-open