Finish milestone

[jennyhickson]

PR Summary

Sci/Tech Reviewer:
Code Reviewer:

New script for closing a milestone from the Review Tracker project during a release. It:

• checks if there are still open PRs against the milestone
• checks if there are closed PRs against another milestone (should they be changed?)
• reports on the number of PRs closed for the milestone
• archives all closed PRs for the milestone
• gives the command for closing the milestone in each repo

To do this it also improves the project data class, simplifying the data structure, including functions for handling milestones and storing the PR details in objects rather than a dictionary.

The user will need to authenticate themselves to modify the project, github prompts for this on first use.

Code Quality Checklist

• I have performed a self-review of my own code
• My code follows the project's style guidelines
• Comments have been included that aid understanding and enhance the readability of the code
• My changes generate no new warnings
• All automated checks in the CI pipeline have completed successfully

Testing

• This change has been tested appropriately (please describe)

Security Considerations

• I have reviewed my changes for potential security issues
• Sensitive data is properly handled (if applicable)
• Authentication and authorisation are properly implemented (if applicable)

AI Assistance and Attribution

• Some of the content of this change has been produced with the assistance of Generative AI tool name (e.g., Met Office Github Copilot Enterprise, Github Copilot Personal, ChatGPT GPT-4, etc) and I have followed the Simulation Systems AI policy (including attribution labels)

Sci/Tech Review

• I understand this area of code and the changes being added
• The proposed changes correspond to the pull request description
• Documentation is sufficient (do documentation papers need updating)
• Sufficient testing has been completed

(Please alert the code reviewer via a tag when you have approved the SR)

Code Review

• All dependencies have been resolved
• Related Issues have been properly linked and addressed
• Code quality standards have been met
• Tests are adequate and have passed
• Security considerations have been addressed
• Performance impact is acceptable