rust-hg-core: upgrade dependencies
This upgrades all dependencies to their latest version, except `clap` and `zstd`
whose latest versions do not support our minimum supported Rust version 1.48.0.
Same as for `rhg`, it contains security fix for `regex` which does not affect
us too much, but doesn't hurt, and the rest of the upgrades are there simply
to keep up.
Differential Revision: https://phab.mercurial-scm.org/D12358
Our full contribution guidelines are in our wiki, please see:
https://www.mercurial-scm.org/wiki/ContributingChanges
If you just want a checklist to follow, you can go straight to
https://www.mercurial-scm.org/wiki/ContributingChanges#Submission_checklist
If you can't run the entire testsuite for some reason (it can be
difficult on Windows), please at least run `contrib/check-code.py` on
any files you've modified and run `python contrib/check-commit` on any
commits you've made (for example, `python contrib/check-commit
273ce12ad8f1` will report some style violations on a very old commit).