Update check

[nemchik]

Pull request

Purpose Users don't know when an update is available. This adds an update check that runs at the beginning of each run of ds that will alert the user if there are new commits to master, and will prompt them to update.

Open Questions and Pre-Merge TODOs Check all boxes as they are completed

• [ ] Test ds -u origin/update_check
• [ ] Updating to test branches is a bit weird. I may need to keep working on this.

Requirements Check all boxes as they are completed

• [x] These changes meet the standards for contributing.
• [x] I have read the code of conduct.