Fix broken protobuf link

Author: kickjet

kv/overview-kv.md

@@ -356,7 +356,7 @@ To make it easy to use the KV proto API in PHP, we provide
 a [GitHub repository](https://github.com/roadrunner-php/roadrunner-api-dto), that contains all the generated PHP DTO
 classes proto files, making it easy to work with these files in your PHP application.
 
-- [API](https://github.com/roadrunner-server/api/blob/master/kv/v1/kv.proto)
+- [API](https://github.com/roadrunner-server/api/blob/master/proto/kv/v1/kv.proto)
 
 ### RPC API