build(deps): bump futures-util from 0.3.4 to 0.3.5

Bumps [futures-util](https://github.com/rust-lang/futures-rs) from 0.3.4 to 0.3.5.
- [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@0.3.4...0.3.5)

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