mypy type annotations fix: replace unicode -> Text

Author: manu-chroma

schema_salad/validate.py

@@ -12,8 +12,6 @@
 
 from typing import Any, List, Set, Union, Text
 from .sourceline import SourceLine, lineno_re, bullets, indent
-import six
-from six.moves import range
 
 _logger = logging.getLogger("salad")