packaging: update dulwich to drop the certifi dependency on Windows
The presence of `certifi` causes the system certificate store to be ignored,
which was reported as a bug against TortoiseHg[1]. It was only pulled in on
Windows because of `dulwich`, which was copied from the old TortoiseHg install
scripts, in order to support `hg-git`.
This version of `dulwich` raises the minimum `urllib3` to a version (1.25) that
does certificate verification by default, without the help of `certifi`[2]. We
already bundle a newer version of `urllib3`. Note that `certifi` can still be
imported from the user site directory, if installed there. But the installer no
longer disables the system certificates by default.
[1] https://foss.heptapod.net/mercurial/tortoisehg/thg/-/issues/5825
[2] https://github.com/jelmer/dulwich/issues/1025
$ hg init
$ echo 123 > a
$ hg add a
$ hg commit -m "first" a
$ mkdir sub
$ echo 321 > sub/b
$ hg add sub/b
$ hg commit -m "second" sub/b
$ cat sub/b
321
$ hg co 0
0 files updated, 0 files merged, 1 files removed, 0 files unresolved
$ cat sub/b 2>/dev/null || echo "sub/b not present"
sub/b not present
$ test -d sub || echo "sub not present"
sub not present