Remove serde derive references (#4830)

* remove remaining uses of serde_derive

* fix lockfile

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Co-authored-by: João Oliveira <hello@jxs.pt>

testing/ef_tests/src/cases/ssz_generic.rs

@@ -4,8 +4,8 @@ use super::*;
 use crate::cases::common::{SszStaticType, TestU128, TestU256};
 use crate::cases::ssz_static::{check_serialization, check_tree_hash};
 use crate::decode::{snappy_decode_file, yaml_decode_file};
+use serde::Deserialize;
 use serde::{de::Error as SerdeError, Deserializer};
-use serde_derive::Deserialize;
 use ssz_derive::{Decode, Encode};
 use std::path::{Path, PathBuf};
 use tree_hash_derive::TreeHash;