DOC: Mention that we provide Python 3.10 wheels
- [ ] closes #42946
- [ ] tests added / passed
- [ ] Ensure all linting tests pass, see [here](https://pandas.pydata.org/pandas-docs/dev/development/contributing.html#code-standards) for how to run them
- [ ] whatsnew entry

IMPORTANT: This depends on MacPython/pandas-wheels#152, so please merge that first.
