Fix to add features: 'derive' for serde

Related-to: GH-10.
Related-to: GH-30.
Related-to: GH-37.
Closes GH-44.
Closes GH-45.

Reviewed-by: Titus Wormer <[email protected]>

Author: kyle-mccarthy

Cargo.toml

@@ -24,7 +24,7 @@ json = ["dep:serde", "dep:serde_json"]
 [dependencies]
 log = "0.4"
 unicode-id = { version = "0.3", features = ["no_std"] }
-serde = { version = "1.0", optional = true }
+serde = { version = "1.0", features = ["derive"], optional = true }
 serde_json = { version = "1.0", optional = true }
 
 [dev-dependencies]