Update hashbrown requirement from 0.14.0 to 0.15.0

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...v0.15.0)

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

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

Cargo.toml

@@ -12,7 +12,7 @@ rust-version = "1.71.1"
 
 [dependencies]
 dlv-list = { version = "0.5", default-features = false }
-hashbrown = { version = "0.14.0", default-features = false }
+hashbrown = { version = "0.15.0", default-features = false }
 serde = { version = "1", optional = true, default-features = false }
 
 [features]