Chore/dependency updates

[jstuczyn]

Where possible, I have updated all dependencies to their most recent version. Understandably, tokio (and tokio-tungstenite et al.) took the longest and some of the updates are slightly "hacky". The notable example of that is using tokio_util::io::poll_read_buf to avoid rewriting common/socks5/proxy-helpers/src/available_reader.rs:AvailableReader to instead use pure AsyncRead with its most recent changes [note: tokio_util is a separate dependency].

There are, however, certain omissions in the packages being updated. They include the following:

• publicsuffix used by service provider (version 1.5) could not be updated to most recent 2.0.X as it's functionality was slightly modified and the library was split into two. Moreover, it no longer downloads the Mozilla's public suffix list by itself, we'd need to do it manually. So for time being let's stick with 1.5 until we feel like we have to update.
• hmac could not be updated to the most recent version. Most recent is 0.10, we stay at 0.8. Reason being is that the recent version of blake3 (0.3.7 at the time of writing) relies on traits defined in crypto-mac 0.8.0. However, it seems the version of blake3 on the master branch has updated the said dependency to the most recent version and hence most likely the next time we deal with updating all of our stuff, we will be able to update this one as well.
• rand was left at 0.7 (most recent is 0.8) as, among other things, we need that version for compatibility with ed25519-dalek crate
• rand_distr was updated only to 0.3 rather than 0.4 as that would require updating rand itself