BUG: GH36212 DataFrame agg() raises error when DataFrame column name is `name`
- [x] closes #36212 
- [x] tests added / passed
- [x] passes `black pandas`
- [x] passes `git diff upstream/master -u -- "*.py" | flake8 --diff`
- [x] whatsnew entry
Hello @leonarduschen! 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 2020-09-12 21:56:55 UTC @jreback @rhshadrach done! thanks @leonarduschen 