fix(proto): enable alloc feature of serde

Author: paolobarbolini

watermelon-proto/Cargo.toml

@@ -20,7 +20,7 @@ percent-encoding = { version = "2", default-features = false, features = ["alloc
 memchr = { version = "2.4", default-features = false }
 unicase = "2.7"
 
-serde = { version = "1.0.113", default-features = false, features = ["derive"] }
+serde = { version = "1.0.113", default-features = false, features = ["alloc", "derive"] }
 serde_json = { version = "1", default-features = false, features = ["alloc"] }
 itoa = "1.0.13"