DOC: whatsnew note for groupby.apply bugfix
ref https://github.com/pandas-dev/pandas/issues/45315#issuecomment-1013655106
- [x] Ensure all linting tests pass, see [here](https://pandas.pydata.org/pandas-docs/dev/development/contributing_codebase.html#pre-commit) for how to run them
- [x] whatsnew entry

thanks @rhshadrach  @meeseeksdev backport 1.4.x Something went wrong ... Please have a look at my logs. I forgot to cc @jbrockmendel - wanted to make sure you're good with the description here. Can do a follow up. this is a great idea