Remove Pandas Restrictions

No longer restrict pandas to be version 1.X. Also, remove explicit support and CI testing for python 3.7, and add CI testing for 3.12.

Normally, due to the loss of functionality for 3.7, we'd call this v3.0, however that is reserved for the new version of the front end.

There should be no functional changes.

What's Changed

• Remove pandas restrictions by @gordonwatts in #358

Full Changelog: v2.7.2...v2.8.0