Bump hashbrown from 0.15.0 to 0.15.2 in /validator in the cargo group

Bumps the cargo group in /validator with 1 update: [hashbrown](https://github.com/rust-lang/hashbrown).


Updates `hashbrown` from 0.15.0 to 0.15.2
- [Changelog](https://github.com/rust-lang/hashbrown/blob/master/CHANGELOG.md)
- [Commits](https://github.com/rust-lang/hashbrown/commits)

---
updated-dependencies:
- dependency-name: hashbrown
  dependency-type: indirect
  dependency-group: cargo
...

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

Author: dependabot[bot]