Fix flake8 linter errors

Author: vduseev

dtcli/validate_schema.py

@@ -3,10 +3,12 @@
 from pathlib import Path
 from typing import Any, List, Union, Callable
 
-import yaml
-from referencing import Registry, Resource
 from jsonschema import Draft202012Validator, Validator, ValidationError
 
+from referencing import Registry, Resource
+
+import yaml
+
 
 YamlAST = Union[yaml.ScalarNode, yaml.SequenceNode, yaml.MappingNode]