Fix compilation issue

Author: 0xVolosnikov

zk_ee/Cargo.toml

@@ -12,7 +12,7 @@ categories.workspace = true
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
-ruint = { workspace = true, default-features = false }
+ruint = { workspace = true, default-features = false, features = ["serde"] }
 arrayvec = { workspace = true, default-features = false }
 serde = { workspace = true, default-features = false, features = ["derive"], optional = true  }