fix pydantic version checking (#80)

Co-authored-by: Shagov <shagov@tochka.com>

Author: mishaga

dirty_equals/_other.py

@@ -229,7 +229,8 @@ def __init__(
             self.RedisDsn = RedisDsn
             self.parse_obj_as = parse_obj_as
             self.ValidationError = ValidationError
-            self.pydantic_version = version.VERSION
+            self.pydantic_version = tuple(map(int, version.VERSION.split('.')))
+
         except ImportError as e:
             raise ImportError('pydantic is not installed, run `pip install dirty-equals[pydantic]`') from e
         url_type_mappings = {
@@ -264,7 +265,11 @@ def equals(self, other: Any) -> bool:
         except self.ValidationError:
             raise ValueError('Invalid URL')
 
-        equal = parsed == other if self.pydantic_version < '2' else parsed.unicode_string() == other
+        if self.pydantic_version[0] == 1:  # checking major version
+            equal = parsed == other
+        else:
+            equal = parsed.unicode_string() == other
+
         if not self.attribute_checks:
             return equal