Update hashbrown requirement from 0.14 to 0.15 (#859)

Updates the requirements on [hashbrown](https://github.com/rust-lang/hashbrown) to permit the latest version.
- [Changelog](https://github.com/rust-lang/hashbrown/blob/master/CHANGELOG.md)
- [Commits](rust-lang/hashbrown@v0.14.0...v0.14.5)

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

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Cargo.toml

@@ -56,7 +56,7 @@ arrayvec = { version = "0.7", default-features = false }
 criterion = "0.5.0"
 educe = "0.6.0"
 digest = { version = "0.10", default-features = false }
-hashbrown = { version = "0.14", default-features = false, features = ["inline-more", "allocator-api2"] }
+hashbrown = { version = "0.15", default-features = false, features = ["inline-more", "allocator-api2"] }
 hex = "0.4"
 itertools = { version = "0.13", default-features = false }
 libtest-mimic = "0.8.1"