fix(docs): remove bracket on file name for broken link (supabase#1493)

## What kind of change does this PR introduce?

A link pointing to a CODE_OF_CONDUCT.md file inside CONTRIBUTING is
broken.

## What is the current behavior?

I removed the unnecessary brackets.

CONTRIBUTING.md

@@ -4,7 +4,7 @@ We would love to have contributions from each and every one of you in the commun
 
 ## Code Of Conduct
 
-Please help us keep all our projects open and inclusive. Kindly follow our [Code of Conduct](<(CODE_OF_CONDUCT.md)>) to keep the ecosystem healthy and friendly for all.
+Please help us keep all our projects open and inclusive. Kindly follow our [Code of Conduct](CODE_OF_CONDUCT.md) to keep the ecosystem healthy and friendly for all.
 
 ## Quick Start