Update to the latest libp2p (#2239)

Updates to the latest libp2p and ignores RUSTSEC-2020-0146 from cargo-audit


Co-authored-by: Michael Sproul <michael@sigmaprime.io>

beacon_node/store/benches/benches.rs

@@ -1,3 +1,5 @@
+#![allow(deprecated)]
+
 use criterion::Criterion;
 use criterion::{black_box, criterion_group, criterion_main, Benchmark};
 use rayon::prelude::*;