Is your feature request related to a problem?

We currently depend on pygit2, which is a C library. This means we have to take extra care that the (latest) pygit2 version contains wheels for all platforms we support.

Describe the solution you'd like

Dulwich may be a good pure-python alternative.

Additional context

Dulwich should support conflict resolution and 3-way merge, since that's what we use under the hood.