py-pygit2: updated to 1.0.2

1.0.2:
Fix enumerating tree entries with submodules

1.0.1:
Fix build in Mac OS

1.0.0:
Drop Python 2.7 and 3.4 support, six no longer required
Add Python 3.8 support
New support for / operator to traverse trees
New Branch.raw_branch_name
New Index.remove_all()
New Remote.ls_remotes(..)
New Repository.lookup_reference_dwim(..) and Repository.resolve_refish(..)
New Repository.odb returns new Odb type instance. And new OdbBackend type.
New Repository.references.compress()
Optimization: Load notes lazily
Fix spurious exception in config
Minor documentation and cosmetic changes

(adam)