Bump gitobj to v2.1.0 to fix merges of tree entries where an
existing tree entry has a different file permissions mode than
the tree entry being merged with it. This should resolve the
problem with import migrations reported in issue #4796 where
existing .gitattributes files with the execute permission mode
set resulted in duplicate .gitattributes tree entries after
import, instead of a single merged entry.
After updating go.mod, the specific commands used for this update
were:
go mod tidy && go mod vendor
h/t bk2204 for spotting the simplest fix for this
133f29f763