Add support for Python 3.12

[amruthvvkp]

Fixes #71

Type of Change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation update
• Other (please describe):

Pre-PR Checklist

• General

  • New code is unit tested.
  • All relevant documentation is updated.
  • This pull request references any related issue by including "closes <link to issue>" (or "fixes" or "resolves"). If the pull request doesn't completely fix the issue, it should include "addresses".
  • Create an issue if this pull request does not completely fix the issue.

• Code changes

  • This pull request includes tests or only affects documentation.
  • This pull request includes a label categorizing the change e.g. bug, feature, enhancement, docs.

Changes

• Updates support for Python 3.12
• Sub-dependency versions updated to support Python 3.7 and 3.8-3.12.
• Added Python 3.12 to Appveyor test matrix.

Checklist

• I have read the contributing guidelines.
• I have followed the code style guidelines.
• I have added tests to cover my changes.
• I have updated the documentation to reflect my changes.
• I have added labels to categorize my changes.
• I have tested my changes locally and they pass all tests.
• I have rebased my branch on the latest main branch.
• I have squashed my commits into a single commit with a descriptive commit message.
• I have signed the contributor license agreement.