Update idna requirement from 0.4 to 0.5

Updates the requirements on [idna](https://github.com/servo/rust-url) to permit the latest version.
- [Release notes](https://github.com/servo/rust-url/releases)
- [Commits](servo/rust-url@v0.4.0...v0.5.0)

---
updated-dependencies:
- dependency-name: idna
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

Cargo.toml

@@ -19,7 +19,7 @@ ethereum-types = "0.14.1"
 futures = "0.3.5"
 futures-timer = "3.0.2"
 hex = "0.4"
-idna = "0.4"
+idna = "0.5"
 jsonrpc-core = "18.0.0"
 log = "0.4.6"
 parking_lot = "0.12.0"