TST: Add a regression test for the timezone issue
Add a regression test to ensure that the timezone doesn't get removed
when using `df.apply`.

- [x] closes #29052
- [x] tests added / passed
- [x] passes `black pandas`
- [x] passes `git diff upstream/master -u -- "*.py" | flake8 --diff`

Hello @GrigoriosGiann! Thanks for updating this PR. We checked the lines you've touched for [PEP 8](https://www.python.org/dev/peps/pep-0008) issues, and found:



There are currently no PEP 8 issues detected in this Pull Request. Cheers! :beers: 

##### Comment last updated at 2019-10-20 10:52:05 UTC > @GrigoriosGiann Thanks for the PR.

Thanks for the feedback! 😄
Let me know if there is anything else I should adjust. 🙂 lgtm. ping on green. Azure appears to be stuck...
Is there a way to rerun checks?
Or should I just `git commit --amend --no-edit` & re-push?

Edit: Force re-pushed since azure failed after some time (https://dev.azure.com/pandas-dev/pandas/_build/results?buildId=19252&view=logs) Ping, it's green!😄  thanks @GrigoriosGiann 