Fix clippy (#2356)

* fix clippy

* temporary ignore RUSTSEC-2022-0093

deny.toml

@@ -50,6 +50,8 @@ notice = "warn"
 ignore = [
     # time (origin: Substrate RPC + benchmarking crates)
     "RUSTSEC-2020-0071",
+    # we are only using it in tests (TODO: https://github.com/paritytech/parity-bridges-common/issues/2355)
+    "RUSTSEC-2022-0093",
 ]
 # Threshold for security vulnerabilities, any vulnerability with a CVSS score
 # lower than the range specified will be ignored. Note that ignored advisories

relays/bin-substrate/src/cli/relay_headers_and_messages/mod.rs

@@ -355,14 +355,14 @@ where
 			let common = self.mut_base().mut_common();
 			substrate_relay_helper::messages::metrics::add_relay_balances_metrics::<_, Self::Right>(
 				common.left.client.clone(),
-				&mut common.metrics_params,
+				&common.metrics_params,
 				&common.left.accounts,
 				&lanes,
 			)
 			.await?;
 			substrate_relay_helper::messages::metrics::add_relay_balances_metrics::<_, Self::Left>(
 				common.right.client.clone(),
-				&mut common.metrics_params,
+				&common.metrics_params,
 				&common.right.accounts,
 				&lanes,
 			)

relays/lib-substrate-relay/src/messages/metrics.rs

@@ -37,7 +37,7 @@ use std::{convert::TryFrom, fmt::Debug, marker::PhantomData};
 /// Add relay accounts balance metrics.
 pub async fn add_relay_balances_metrics<C: ChainWithBalances, BC: ChainWithMessages>(
 	client: impl Client<C>,
-	metrics: &mut MetricsParams,
+	metrics: &MetricsParams,
 	relay_accounts: &Vec<TaggedAccount<AccountIdOf<C>>>,
 	lanes: &[LaneId],
 ) -> anyhow::Result<()>