Remove v1.2.0 'with-serde' feature compatibility shim. Just use 'serde' now.

Cargo.toml

@@ -15,6 +15,3 @@ serde = { version = "1", features = ["derive"], optional = true }
 
 [dev-dependencies]
 serde_test = "1"
-
-[features]
-with-serde = ["serde"] # Compatibility shim for 1.1.0. Use `serde` instead.

src/lib.rs

@@ -87,4 +87,4 @@ mod ipext;
 mod ipnet;
 mod parser;
 #[cfg(feature = "serde")]
-mod with_serde;
+mod ipnet_serde;