BUG: GH13219 Fixed. Allow unicode values in usecol
- [x] closes #13219 
- [x] tests added / passed
- [x] passes `git diff upstream/master | flake8 --diff`
- [x] whatsnew entry

This is my first time contributing to this project.  Let me know what needs to be improved, especially with regards to the test and the bugfix.  It was simpler than I imagined which makes me want to say I did it wrong.
