Better track stage wide code changes in Secure

Problem to solve

From the 12.7 retrospective:

Even if we're split by different groups, we still need to follow the features (in the Rails codebase) developed by all the Secure stage.

Proposal

During the retro, some suggestions were made:

• ask for a review from another member of the Secure stage.
• callout these changes in the weekly stage meeting (announcement, video)
• over communicate in slack