Update futures and futures-core

[williamdes]

It was locked by 29d09b5

Since the commit does not state why, and that Rust is unsatisfied. I upgraded the lib and it builds.

    Updating crates.io index
error: failed to select a version for `futures-core`.
    ... required by package `futures-util v0.3.31`
    ... which satisfies dependency `futures-util = "^0.3.16"` of package `futures v0.3.16`
    ... which satisfies dependency `futures = "=0.3.16"` of package `rustybgpd v0.2.0 (/mnt/Dev/@williamdes/@forked-repos/rustybgp/daemon)`
versions that meet the requirements `^0.3.31` are: 0.3.31

all possible versions conflict with previously selected packages.

  previously selected package `futures-core v0.3.16`
    ... which satisfies dependency `futures-core = "=0.3.16"` of package `rustybgpd v0.2.0 (/mnt/Dev/@williamdes/@forked-repos/rustybgp/daemon)`

failed to select a version for `futures-core` which could resolve this conflict