Chore: Offboarding update for humans.txt (#48919)

Removed Dustin Keib from the list of contributors.

## I have read the
[CONTRIBUTING.md](https://github.com/supabase/supabase/blob/master/CONTRIBUTING.md)
file.

YES

## What kind of change does this PR introduce?

Doc update




<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->

## Summary by CodeRabbit

* **Documentation**
* Removed a former team member from the publicly displayed team
information.

<!-- end of auto-generated comment: release notes by coderabbit.ai -->

apps/docs/public/humans.txt

@@ -90,7 +90,6 @@ Div Arora
 Divit D
 Divya Sharma
 Douglas Hunley
-Dustin Keib
 Eduardo Gurgel
 Eleftheria Trivyzaki
 Eliot Whalan