Consider `setuptools_scm`

[fosskers]

Describe the bug

https://pypi.org/project/setuptools-scm-git-archive/, as introduced in #44, is unfortunately deprecated. It is suggested that setuptools_scm is used instead.

This was brought to my attention by a downstream user, so I'm passing the suggestion along.

Thank you for your time.

[gnikit]

We don't use .git_archival.txt other than removing the dependency and using and pinning the lower version is there something else that needs to be done?

[fosskers]

According to https://github.com/Changaco/setuptools_scm_git_archive#migration-guide that should be sufficient?