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