Deny unused crate dependencies (#549)

* subxt unused crate deps

* Deny unused dependencies

subxt/Cargo.toml

@@ -41,10 +41,5 @@ frame-metadata = "15.0.0"
 derivative = "2.2.0"
 
 [dev-dependencies]
-sp-arithmetic = { version = "5.0.0", default-features = false }
 assert_matches = "1.5.0"
 tokio = { version = "1.8", features = ["macros", "time"] }
-tempdir = "0.3.7"
-wabt = "0.10.0"
-which = "4.0.2"
-sp-keyring = "6.0.0"

subxt/src/lib.rs

@@ -35,6 +35,7 @@
     while_true,
     trivial_casts,
     trivial_numeric_casts,
+    unused_crate_dependencies,
     unused_extern_crates,
     clippy::all
 )]