Update to rust edition 2021 everywhere (#1086)

* chore: update to rust edition 2021 everywhere

* validator-api: simplify into_iter call in rust 2021

validator-api/Cargo.toml

@@ -9,7 +9,7 @@ authors = [
     "Jędrzej Stuczyński <andrew@nymtech.net>",
     "Drazen Urch <durch@users.noreply.github.com>",
 ]
-edition = "2018"
+edition = "2021"
 rust-version = "1.56"
 
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html

validator-api/src/network_monitor/test_route/mod.rs

@@ -23,13 +23,12 @@ impl TestRoute {
         l3_mix: mix::Node,
         gateway: gateway::Node,
     ) -> Self {
-        // When somebody gets to refactor this in the future and Rust 2021 is being used,
-        // the call could be changed to a simple `.into_iter()`
-        let layered_mixes = IntoIterator::into_iter([
+        let layered_mixes = [
             (1u8, vec![l1_mix]),
             (2u8, vec![l2_mix]),
             (3u8, vec![l3_mix]),
-        ])
+        ]
+        .into_iter()
         .collect();
 
         TestRoute {