pre-commit can not deal with rename directory about unity-git-hooks

[doitian]

Test case to reproduce:

1. Add a directory and its meta file to git. Git does not allow adding a directory, so add a .gitkeep file in the directory.
2. Rename the directory without renaming the meta file.

• Expected result: pre-commit should report the error
• Real result: pre-commit passed
• Cause: git diff will exclude detected renames from adds and deletes, so the script does not check all renames.

@test "renaming directory" {
  mkdir Assets/dir
  touch Assets/dir/.gitkeep
  touch Assets/dir.meta
  git add --force --all
  git commit -n -m 'add Assets/dir'
  mv Assets/dir Assets/dir-new
  git add --force --all
  run "$PRE_COMMIT"
  [ "$status" -eq 0 ]
}