See:
 - https://github.com/libgit2/pygit2/issues/1018#issuecomment-696392171
 - https://github.com/presslabs/gitfs/issues/323

--- gitfs/mounter.py.orig	2019-10-20 13:00:10.000000000 +0200
+++ gitfs/mounter.py	2020-10-03 14:26:43.000000000 +0200
@@ -19,7 +19,7 @@

 from fuse import FUSE
 from pygit2 import Keypair, UserPass
-from pygit2.remote import RemoteCallbacks
+from pygit2.callbacks import RemoteCallbacks

 from gitfs import __version__
 from gitfs.utils import Args