Fix clippy

Author: thomaseizinger

protocols/gossipsub/src/subscription_filter_priv.rs

@@ -213,7 +213,6 @@ impl TopicSubscriptionFilter for RegexSubscriptionFilter {
 mod test {
     use super::*;
     use crate::types::SubscriptionAction::*;
-    use regex::Regex;
     use std::iter::FromIterator;
 
     #[test]