Implement exercise T4L2/tags-update

[jovnc]

Exercise Review

Exercise Discussion

Fixes #62

Checklist

• If you require a new remote repository on the Git-Mastery organization, have you created a request for it?
• Have you written unit tests using repo-smith to validate the exercise grading scheme?
• Have you tested the download script using test-download.sh?
• Have you verified that this exercise does not already exist or is not currently in review?
• Did you introduce a new grading mechanism that should belong to git-autograder?
• Did you introduce a new dependency that should belong to app?

[jovnc]

Opened PR early while waiting to be assigned. Feel free to close if there are duplicates in the future, or if someone else is assigned to this exercise in the future.

This would serve as potential reference to others looking for implementations of exercises as well.

[woojiahao]

Thank you @jovnc for working on this exercise! I think that there are some major comments on the ordering of grading, less on the coding style, more so on the autograding philosophy. I will need to update the public documentation to capture this logic too

[jovnc]

@woojiahao Thanks for the PR review, and the very detailed comments. I have made the changes based on your comments, namely here are the main changes:

1. modified tag util function to also take in optional parameter commit_ref
2. add new test for wrong january-tag
3. reorder verification process to follow order of the task

[VikramGoyal23]

LGTM, let's wait for @woojiahao's input on the change to the tag function.

[jovnc]

Given there is a new utility function tag_with_options, I'll refactor to use that instead

[jovnc]

@VikramGoyal23 @woojiahao I have made some changes, and would like to ask for a review again, thanks! If there are any changes, do let me know and I'll quickly make the changes, otherwise we can merge this PR