chore: bump tokio-util to 0.7.13

[yihau]

Summary of Changes

bump it

[KirillLykov]

Bumping this version would allow to use some new features of this crate, simplifying the code. The one I use is that cancellation token now has method https://docs.rs/tokio-util/latest/tokio_util/sync/struct.CancellationToken.html#method.run_until_cancelled

Why it is better to specify full version rather than minor like it was -- in some CI checks cargo pick ups version 0.7.13 (last one) but sometimes it picks 0.7.11 which doesn't have some methods.

There is a very low risk of breaking something with bumping the version because this crate contains limited functionality and because the changes between 11 and 13 are quite minimal (but simplifying life as I said).

[mergify]

Backports to the beta branch are to be avoided unless absolutely necessary for fixing bugs, security issues, and perf regressions. Changes intended for backport should be structured such that a minimum effective diff can be committed separately from any refactoring, plumbing, cleanup, etc that are not strictly necessary to achieve the goal. Any of the latter should go only into master and ride the normal stabilization schedule. Exceptions include CI/metrics changes, CLI improvements and documentation updates on a case by case basis.