fix: contribution guide

CONTRIBUTING.md

@@ -42,15 +42,18 @@ To just check for lint errors, run:
 
 To run against a particular Python version:
 
- nox --session tests-3.8
- nox --session tests-3.9
- nox --session tests-3.10
- nox --session tests-3.11
- nox --session tests-3.12
+ nox --session "tests(python='3.12', tox_version='latest')
+ nox --session conda_tests
+ nox --session mamba_tests
+ nox --session micromamba_tests
 
 When you send a pull request the CI will handle running everything, but it is
 recommended to test as much as possible locally before pushing.
 
+You can list all possible tests with:
+
+ nox --list-sessions
+
 ## Getting a sticker
 
 If you've contributed to Nox, you can get a cute little Nox sticker. Reach out to Thea at [email protected] to request one.