Bump tokio-util from 0.3.0 to 0.3.1
Bump tokio-util from 0.3.0 to 0.3.1

Bumps [tokio-util](https://github.com/tokio-rs/tokio) from 0.3.0 to 0.3.1.
- [Release notes](https://github.com/tokio-rs/tokio/releases)
- [Commits](https://github.com/tokio-rs/tokio/commits)

Signed-off-by: dependabot-preview[bot] <5bdcd3c0d4d24ae3e71b3b452a024c6324c7e4bb@dependabot.com>
Closes: #3035
Approved by: rexhoffman

libra/libra,aptos-labs/aptos-core,aptos-labs/aptos-core,aptos-labs/aptos-core,libra/libra,libra/libra,aptos-labs/aptos-core,aptos-labs/aptos-core,aptos-labs/aptos-core,aptos-labs/aptos-core,libra/libra,libra/libra