Upgrades python to version 3.12

[DrPaulSharp]

Description

Upgrades the minimum version of SasView to 3.12, following the upgrade to SasData in SasView/sasdata#166. This should fix the broken CI which was broken due to the clash in python versions.

How Has This Been Tested?

Ran the CI.

Review Checklist:

[if using the editor, use [x] in place of [ ] to check a box]

Documentation (check at least one)

• There is nothing that needs documenting
• Documentation changes are in this PR
• There is an issue open for the documentation (link?)

Installers

• There is a chance this will affect the installers, if so
  • Windows installer (GH artifact) has been tested (installed and worked)
  • MacOSX installer (GH artifact) has been tested (installed and worked)
  • Wheels installer (GH artifact) has been tested (installed and worked)

Licensing (untick if necessary)

• The introduced changes comply with SasView license (BSD 3-Clause)