build(deps): bump futures from 0.3.30 to 0.3.31

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]>

Author: dependabot[bot]

Cargo.lock

@@ -12,7 +12,7 @@ publish = false
 
 [dependencies]
 env_logger = "^0.10.1"
-futures = "^0.3.30"
+futures = "^0.3.31"
 log = "^0.4.22"
 prost = "^0.13"
 structopt = "^0.3.26"