Bump futures from 0.3.30 to 0.3.31 (#3060)

Bumps [futures](https://github.com/rust-lang/futures-rs) from 0.3.30 to 0.3.31.
- [Release notes](https://github.com/rust-lang/futures-rs/releases)
- [Changelog](https://github.com/rust-lang/futures-rs/blob/master/CHANGELOG.md)
- [Commits](rust-lang/futures-rs@0.3.30...0.3.31)

---
updated-dependencies:
- dependency-name: futures
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Branislav Kontur <[email protected]>

substrate-relay/Cargo.toml

@@ -15,7 +15,7 @@ async-std = "1.13.0"
 async-trait = "0.1.83"
 codec = { package = "parity-scale-codec", version = "3.6.1" }
 env_logger = "0.11"
-futures = "0.3.30"
+futures = "0.3.31"
 hex = "0.4"
 log = { workspace = true }
 num-format = "0.4"