Bump tokio from 1.39.2 to 1.39.3 in /rustclient/lib (#240)

Bumps [tokio](https://github.com/tokio-rs/tokio) from 1.39.2 to 1.39.3.
- [Release notes](https://github.com/tokio-rs/tokio/releases)
- [Commits](tokio-rs/tokio@tokio-1.39.2...tokio-1.39.3)

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

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Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>