enable conf serde and test the toml format with our current schema

Cargo.toml

@@ -26,8 +26,8 @@ prometheus-http-client = { path = "prometheus-http-client", default-features = f
 
 async-trait = "0.1"
 chrono = { version = "0.4", default-features = false, features = ["clock", "serde", "std"] }
-chrono-tz = "0.10"
-conf = "0.4"
+chrono-tz = { version = "0.10", features = ["serde"] }
+conf = { version = "0.4", features = ["serde"] }
 conf-extra = "0.1"
 displaydoc = "0.2"
 dotenvy = "0.15"
@@ -46,6 +46,7 @@ serde = { version = "1", features = ["derive"] }
 serde_json = "1"
 syslog_rfc5424 = "0.10"
 thiserror = "2"
+toml = "0.8"
 tokio = { version = "1", features = ["macros", "net", "sync", "time"] }
 tokio-util = { version = "0.7", features = ["codec"] }
 tracing = "0.1"