add examle PyPI upload example

[heather999]

IMPORTANT: Please create an issue first before opening a Pull Request. Linked to issue(s): #255

Type of change

Please delete options that are not relevant.

• [x] New feature (non-breaking change which adds functionality)

What changes were proposed in this pull request?

Adding new GH Action to automate upload to PyPI for new releases

How was this patch tested?

Has not been tested directly with snmachine yet. Once a new GitHub secret is added, we can see how this workflow functions using the testPyPI to start

Final Checklist:

• [ ] My code follows the style guidelines of this project
• [ ] I have made corresponding changes to the documentation
• [ ] I have added tests that prove my fix is effective or that my feature works
• [ ] I am up to date with dev branch of snmachine at the time of this PR