Count binary files as zero insertions

Hyphens are the only nonn-numeric characters that should show up here. See: https://git-scm.com/docs/git-log#Documentation/git-log.txt---numstat

Author: ianhi

jupyterlab_git/git.py

@@ -330,6 +330,8 @@ async def detailed_log(self, selected_hash, current_path):
         line_iterable = iter(strip_and_split(my_output)[1:])
         for line in line_iterable:
             insertions, deletions, file = line.split('\t')
+            insertions = insertions.replace('-', '0')
+            deletions = deletions.replace('-', '0')
 
             if file == '':
                 # file was renamed or moved, we need next two lines of output