Remove direct dependency on futures-lite

[link2xt]

#skip-changelog

[link2xt]

futures should probably be replaced with futures-lite if possible, because futures-lite is a dependency of async-std anyway and futures-lite is much smaller and easier to review. But it's a different issue. Here the use of futures-lite was completely unnecessary.

[link2xt]

After move from async-std to tokio we only depend on futures-lite directly, so closing this. futures-lite cannot be replaced with futures easily because it has some nice APIs like .race() that futures does not have.