Deny unused crate dependencies (#549)

* subxt unused crate deps

* Deny unused dependencies

integration-tests/Cargo.toml

@@ -16,7 +16,6 @@ default = ["subxt/integration-tests"]
 
 [dev-dependencies]
 assert_matches = "1.5.0"
-async-trait = "0.1.49"
 codec = { package = "parity-scale-codec", version = "3.0.0", default-features = false, features = ["derive", "full", "bit-vec"] }
 frame-metadata = "15.0.0"
 futures = "0.3.13"

integration-tests/src/lib.rs

@@ -14,6 +14,8 @@
 // You should have received a copy of the GNU General Public License
 // along with subxt.  If not, see <http://www.gnu.org/licenses/>.
 
+#![deny(unused_crate_dependencies)]
+
 #[cfg(test)]
 mod codegen;
 #[cfg(test)]