2024 Q4 Holiday checker for GHA

User Story

As the managers and engineers of vets-api, We need to see if the new GHA holiday checker is something we want to leverage for vets-api, So that code isn't deployed during the holidays.

Issue Description

Discovery to see how to standardize this across teams. Infra is currently using this in multiple repos.

Vets-api currently uses sync-windows to prevent code from being deployed on holidays. (We also have a yearly reminder to update the dates.) But we may want to leverage infra's holiday checker in our build/deploy action as well for another safety layer or to align with things others on the Platform are doing.

New custom action: https://github.com/department-of-veterans-affairs/vsp-github-actions/tree/main/holiday-checker
Example usage: https://github.com/department-of-veterans-affairs/vsp-platform-revproxy/pull/655

Things to keep in mind

We still deploy dev and staging during holidays
There is a manual process to holiday code freezes, no matter which approach we take: the dates for some holidays change every year. So the dates need to be updated manually and if we leverage holiday-checker in addition to sync-windows, we're now tied to and dependent on infra changing those dates every year.
We could abandon sync-windows and switch to holiday-checker but... sync-windows seem to be working just fine.

Tasks

[ ] Review and see about leveraging sync-windows in our build/deploy actions
[ ] Document pros and cons

Success Metrics

We are confident in our holiday code freeze process for vets-api.

Acceptance Criteria

[ ] holiday-checker GHA is either implemented or not implemented, depending on research.

Validation

Assignee to add steps to this section. List the actions that need to be taken to confirm this issue is complete. Include any necessary links or context. State the expected outcome.

department-of-veterans-affairs / va.gov-team