Use yaml_serde in place of deprecated serde_yaml (#9040)

`serde_yaml` is now deprecated. The API-compatible `yaml_serde` should be used instead.


  Replace `serde_yaml` with `yaml_serde`. This is purely mechanical as the API is 1-to-1.


Co-Authored-By: Mac L <mjladson@pm.me>

beacon_node/client/Cargo.toml

@@ -42,6 +42,6 @@ types = { workspace = true }
 
 [dev-dependencies]
 operation_pool = { workspace = true }
-serde_yaml = { workspace = true }
 state_processing = { workspace = true }
 tokio = { workspace = true }
+yaml_serde = { workspace = true }