Log Message:
py-dulwich: updated to 0.20.50

0.20.50 2022-10-30

* Fix Repo.reset_index.
  Previously, it instead took the union with the given tree.
* Add -b argument to ``dulwich clone``.
* On Windows, provide a hint about developer mode
  when creating symlinks fails due to a permission
  error.
* Add new ``ObjectID`` type in ``dulwich.objects``,
  currently just an alias for ``bytes``.
* Support repository format version 1.
* Support \r\n line endings with continuations when parsing
  configuration files.
* Fix handling of SymrefLoop in RefsContainer.__setitem__.