def item( was broken
`pd.DataFrame({"a":[1,2,3]}).a.item() ` -- breaks! 
`pd.DataFrame({"a":[1,2,3]}).a.values.item(0)` --- this is actual expected behaviour

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