Added Python 3.12 to tests.

[RoryBarnes]

Changed upload_pypi in pip-install to work on all OSes

Proposed changes

Describe your changes here to communicate to the maintainers the value of this pull request (PR). If it fixes a bug or resolves a feature request, be sure to link to that issue.

Types of changes

What types of changes does your PR introduce to VPLanet?
Put an x in the boxes that apply

• Bugfix (non-breaking change that fixes an issue)
• New feature (non-breaking change that adds functionality)
• New module (non-breaking change that adds a new module)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation update

Checklist

Put an x in the boxes that apply. You can also fill these out after creating the PR. If you're unsure about any of them, don't hesitate to ask. We're here to help! This is simply a reminder of the steps that are necessary before merging your PR.

• I have added tests that prove my fix is effective or that my feature works
• I have adhered to the Style or run the clang format code shown here
• I have added necessary documentation (if appropriate)
• I have run Valgrind on new tests to ensure no errors were found
• (Optional) I have added an example showcasing the new change

Further comments

If this is a relatively large or complex change, explain why you chose the solution you did, what alternatives you considered, or anything else you believe to be relevant.

[github-actions]

Test Results

19 599 tests   19 599 ✅  1m 34s ⏱️
     1 suites       0 💤
     1 files         0 ❌

Results for commit 4ed1d3f.