Update rand requirement from 0.8 to 0.9

Updates the requirements on [rand](https://github.com/rust-random/rand) to permit the latest version.
- [Release notes](https://github.com/rust-random/rand/releases)
- [Changelog](https://github.com/rust-random/rand/blob/master/CHANGELOG.md)
- [Commits](rust-random/rand@0.8.0...0.9.0)

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

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

Cargo.toml

@@ -25,7 +25,7 @@ zeroize = { version = "1", default-features = false, optional = true }
 serde = { version = "1", default-features = false, optional = true }
 
 [dev-dependencies]
-rand = "0.8"
+rand = "0.9"
 signature = { version = "2.0", default-features = false }
 criterion = { version = "0.5", default-features = false }
 bls12_381 = { version = "0.8", default-features = false, features = [