moved git tags info from user install into developer install

[shimwell]

Description

This PR moves some text from the user install into the developer install section of the docs. Also fixed a typo and added the repo url as the upstream. I believe this should be in the developer install instructions instead of the user install as it is only related to installing via github and unrelated to the conda install

Checklist

• [x] I'm making a PR from a feature branch on my fork into GEOUNED-org/GEOUNED/dev branch
• [ ] I have followed PEP8 style guide for Python or run a formatter such as black or ruff format on my code
• [x] I have made corresponding changes to the documentation
• [ ] I have added tests that prove my fix is effective or that my feature works