I’ld like to have this mercurial extension available from the same repositories as mercurial itself.

The build on Leap 15.3 requires `python-dulwich` from `devel:languages:python` (which could be added using `osc linkpac devel:languages:python python-dulwich devel:tools:scm`), and additionally for Leap 15.2, `python-dulwich` requires `python-urllib3`, also from `devel:languages:python` (although support for 15.2 could reasonably be ignored).