docs(repo): correct deprecation announcement link

Author: mandarini

docs/MIGRATION.md

@@ -85,7 +85,7 @@ npm install @supabase/[email protected]
 
 ### Discussion
 
-For more details, see the [deprecation announcement](https://github.com/supabase/supabase-js/discussions/37217).
+For more details, see the [deprecation announcement](https://github.com/orgs/supabase/discussions/37217).
 
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