docs: update example config directory link in readme

Author: shiyasmohd

README.md

@@ -21,7 +21,7 @@ Usage: indexer-service-rs --config <FILE>
 
 Options:
       --config <FILE>  Path to the configuration file.
-                       See https://github.com/graphprotocol/indexer-rs/tree/main/service for examples.
+                       See https://github.com/graphprotocol/indexer-rs/tree/main/config for examples.
   -h, --help           Print help
 ```