BUG: Coercing bool types to int in qcut
- [x] closes #20303 
- [x] tests added / passed: `pytest pandas/tests/reshape/test_qcut.py pandas/tests/reshape/test_cut.py -v` 
- [x] passes `black pandas`
- [x] passes `git diff upstream/master --name-only -- "*.py" | xargs flake8`
- [x] whatsnew entry
