Bump rand from 0.7.3 to 0.8.5

Bumps [rand](https://github.com/rust-random/rand) from 0.7.3 to 0.8.5.
- [Release notes](https://github.com/rust-random/rand/releases)
- [Changelog](https://github.com/rust-random/rand/blob/master/CHANGELOG.md)
- [Commits](https://github.com/rust-random/rand/compare/0.7.3...0.8.5)

---
updated-dependencies:
- dependency-name: rand
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

bridges/relays/client-substrate/Cargo.toml

@@ -13,7 +13,7 @@ futures = "0.3.26"
 jsonrpsee = { version = "0.15", features = ["macros", "ws-client"] }
 log = "0.4.17"
 num-traits = "0.2"
-rand = "0.7"
+rand = "0.8"
 scale-info = { version = "2.1.1", features = ["derive"] }
 tokio = { version = "1.25", features = ["rt-multi-thread"] }
 thiserror = "1.0.26"