Tweaks to update post

[MattIPv4]

Description

Title is now properly styled as a title:

Added updated date in the same style as our previous post, with the date based on when we shipped this update to production:

Added a line between the two posts to make the separation clearer:

Striked out the opt-out update, added updated copy pointing to the updated response + opt-in:

Test process

All looks correct

Requirements to merge

• [x] My code follows the style guidelines of this project
• [x] I have performed a self-review of my own code
• [ ] I have commented my code in hard-to-understand areas
• [x] My changes generate no new warnings
• [ ] I have added tests that prove my fix is effective or that my feature works
• [x] New and existing unit tests pass locally with my changes