Define 'serde' cfg feature for generated modules

Author: hchataing

pdl-derive/Cargo.toml

@@ -15,6 +15,9 @@ authors = [
 exclude = ["editors/*"]
 categories = ["parsing"]
 
+[features]
+serde = []
+
 [lib]
 name = "pdl_derive"
 proc-macro = true

pdl-tests/Cargo.toml

@@ -5,6 +5,9 @@ publish = false
 edition = "2021"
 description = "PDL Rust generated code tests"
 
+[features]
+serde = []
+
 [dependencies]
 bytes = "1.4.0"
 thiserror = "1.0.47"