Require up-to-date x25519-dalek, async_executors, and argh.

I tried using -Z minimal-versions to downgrade all first-level
dependencies to their oldest permitted versions, and found that we
were apparently depending on newer features of all three crates.

I'm kind of surprised there were only three.

crates/arti/Cargo.toml

@@ -32,5 +32,5 @@ once_cell = { version = "1.7.2", optional = true }
 serde = { version = "1.0.124", features = ["derive"] }
 tracing-subscriber = "0.2.19"
 tokio-crate = { package="tokio", version = "1.7.0", optional = true, features = ["signal"] }
-argh = "0.1.4"
+argh = "0.1.6"
 tracing-journald = { version = "0.1.0", optional = true }

crates/tor-llcrypto/Cargo.toml

@@ -28,7 +28,7 @@ serde = "1.0.124"
 signature = "1.3.0"
 simple_asn1 = "0.5.1"
 subtle = "2.4.0"
-x25519-dalek = "1.1.1"
+x25519-dalek = "1.2.0"
 zeroize = "1.3.0"
 thiserror = "1.0.24"
 

crates/tor-rtcompat/Cargo.toml

@@ -19,7 +19,7 @@ static = [ "native-tls/vendored" ]
 
 [dependencies]
 
-async_executors = { version = "0.4.0", default_features=false }
+async_executors = { version = "0.4.2", default_features = false }
 async-trait = "0.1.48"
 futures = "0.3.13"
 pin-project = "1.0.5"