switch Rcu to the arcu crate

The arcu crate is a more general implementation of the Rcu I implemented in here in scryer. It contains some bug-fixes regarding race-conditions in the Rcu update function, which could cause leaks and uses after free.

Source of the problem was the Relaxed load/strore/update of the reference count in side the Arc not being properly ordered with other load/stores.

Cargo.toml

@@ -74,6 +74,7 @@ static_assertions = "1.1.0"
 
 serde_json = "1.0.95"
 serde = "1.0.159"
+arcu = { version = "0.1.1", features = ["thread_local_counter"] }
 
 [target.'cfg(not(target_arch = "wasm32"))'.dependencies]
 crossterm = { version = "0.20.0", optional = true }