Update criterion requirement from 0.3 to 0.4

Updates the requirements on [criterion](https://github.com/bheisler/criterion.rs) to permit the latest version.
- [Release notes](https://github.com/bheisler/criterion.rs/releases)
- [Changelog](https://github.com/bheisler/criterion.rs/blob/master/CHANGELOG.md)
- [Commits](bheisler/criterion.rs@0.3.0...0.4.0)

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

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

Cargo.toml

@@ -18,7 +18,7 @@ once_cell = "1"
 waker-fn = "1"
 
 [dev-dependencies]
-criterion = "0.3"
+criterion = "0.4"
 futures-timer = "3"
 rusty_pool = "0.7"
 threadpool = "1"