Adds a `name` attribute to `Spinner`

[KaiSforza]

Makes it nicer for validation and use of the Spinner object in later functions/classes.

Type of changes

• [ ] Bug fix
• [x] New feature
• [ ] Documentation / docstrings
• [ ] Tests
• [ ] Other

Checklist

• [x] I've run the latest black with default args on new code.
• [x] I've updated CHANGELOG.md and CONTRIBUTORS.md where appropriate.
• [ ] I've added tests for new code. (not really much need, let me know if I should add an assert or something though.)
• [x] I accept that @willmcgugan may be pedantic in the code review.

Description

Simply adds a name attribute to Spinner for use in later functions/classes. The current one has no mention of name outside of __init__, but a lot of the functions and classes take a spinner name, not a spinner object. I added this because of some of the stuff I did in pypa/hatch#1490. Would have been nice to make it not a throwaway.

[willmcgugan]

I don't quite follow why you need this. Can you elaborate?