Update rand_core requirement

Updates the requirements on [rand_core](https://github.com/rust-random/rand) to permit the latest version.

Updates `rand_core` to 0.6.4
- [Release notes](https://github.com/rust-random/rand/releases)
- [Changelog](https://github.com/rust-random/rand/blob/master/CHANGELOG.md)
- [Commits](rust-random/rand@rand_core-0.6.0...rand_core-0.6.4)

---
updated-dependencies:
- dependency-name: rand_core
  dependency-type: direct:production
  dependency-group: dependencies
...

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

Author: dependabot[bot]

Cargo.toml

@@ -14,7 +14,7 @@ thiserror = "2.0.8"
 zip = { version = "2.0.0", default-features = false }
 
 # Cannot be newer than `ed25519-dalek`'s dependency
-rand_core = { version = "0.6.0", features = ["getrandom"] }
+rand_core = { version = "0.9.0", features = ["getrandom"] }
 
 [workspace.dependencies.zipsign-api]
 version = "0.1.3"