fix: fix link to Rivet Bluesky Profile.

[zicklag]

Description

The previous link linked to rivet.dev as the handle, when the actual handle is rivet.gg.

I had previously tried and failed to follow Rivet using the link at the bottom of the website and only found the actual profle on the GitHub README.

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

How Has This Been Tested?

Not at all.

Checklist:

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