BUG: construction from dt64/td64 values with td64/dt64 dtype
- [ ] closes #xxxx
- [x] tests added / passed
- [x] passes `black pandas`
- [x] passes `git diff upstream/master -u -- "*.py" | flake8 --diff`
- [x] whatsnew entry

this is a sligth user facing change rigth? e.g. add a whatsnew whatsnew added + greenish