rhg: upgrade dependencies
This upgrades all dependencies to their latest version, except `clap`, which
is upgraded to the last 2.x series version, since 3.x does not support our
minimum supported Rust version of 1.48.0.
This contains a 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/D12357
Mercurial
=========
Mercurial is a fast, easy to use, distributed revision control tool
for software developers.
Basic install::
$ make # see install targets
$ make install # do a system-wide install
$ hg debuginstall # sanity-check setup
$ hg # see help
Running without installing::
$ make local # build for inplace usage
$ ./hg --version # should show the latest version
See https://mercurial-scm.org/ for detailed installation
instructions, platform-specific notes, and Mercurial user information.
Notes for packagers
===================
Mercurial ships a copy of the python-zstandard sources. This is used to
provide support for zstd compression and decompression functionality. The
module is not intended to be replaced by the plain python-zstandard nor
is it intended to use a system zstd library. Patches can result in hard
to diagnose errors and are explicitly discouraged as unsupported
configuration.