DEPS: Bump PyArrow to 6.0
- [x] closes #48014 (Replace xxxx with the GitHub issue number)
- [x] [Tests added and passed](https://pandas.pydata.org/pandas-docs/dev/development/contributing_codebase.html#writing-tests) if fixing a bug or adding a new feature
- [x] All [code checks passed](https://pandas.pydata.org/pandas-docs/dev/development/contributing_codebase.html#pre-commit).
- [ ] Added [type annotations](https://pandas.pydata.org/pandas-docs/dev/development/contributing_codebase.html#type-hints) to new arguments/methods/functions.
- [x] Added an entry in the latest `doc/source/whatsnew/vX.X.X.rst` file if fixing a bug or adding a new feature.


Would help https://github.com/pandas-dev/pandas/pull/47781 and https://github.com/pandas-dev/pandas/pull/49078

1.0.1 was released on August 21, 2020 and 5.0.0 was released July 28 2021 (almost a year later).

Last time optional dependencies were bumped (https://github.com/pandas-dev/pandas/pull/47048), the versions were based on the version released ~1 year _prior_, so given that logic, could even bump to 6.0.0 (October 26, 2021)
> could even bump to 6.0.0

Go for it.  For a major release I think we're OK being really aggressive on this front. I would also be +1 to a 6.0 bump +1 in 6.0 as well thx @mroeschke 