chore(docs): add Matt McGill to humans.txt (#51610)

## Problem

I joined Supabase!

## Solution

I've recorded that I joined Supabase!

## Checklist

Check all before review:

- [x] I have read
[CONTRIBUTING.md](https://github.com/supabase/supabase/blob/master/CONTRIBUTING.md)
- [ ] If I wrote a new docs topic or edited an existing topic, I used
the `/write-the-docs` or `/edit-the-docs` skill, which applies the docs
[style
guide](https://github.com/supabase/supabase/tree/master/apps/docs/style-guide)

apps/docs/public/humans.txt

@@ -231,6 +231,7 @@ Márton Boros
 Matthew Hambright
 Matt Hudson
 Matt Johnston
+Matt McGill
 Matt Robinson
 Matt Rossman
 Matt Smiley