Remove `basepython` restriction in `lint` and `coverage` environments

[garrison]

This restriction was previously necessary, but it no longer appears to be, as far as I can tell.

Getting rid of the restriction will make these environments work on systems where python3.10 is not installed.

[coveralls]

Pull Request Test Coverage Report for Build 9309068398

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 100.0%

---

Totals
Change from base Build 9306464756:	0.0%
Covered Lines:	2401
Relevant Lines:	2401

---

💛 - Coveralls