Use default setuptools-scm value for tag-pattern instead of empty s…

…tring

Closes ofek#67

hatch_vcs/version_source.py

@@ -1,6 +1,8 @@
 # SPDX-FileCopyrightText: 2022-present Ofek Lev <oss@ofek.dev>
 #
 # SPDX-License-Identifier: MIT
+import re
+
 from hatchling.version.source.plugin.interface import VersionSourceInterface
 
 
@@ -17,8 +19,9 @@ def __init__(self, *args, **kwargs):
     @property
     def config_tag_pattern(self):
         if self.__config_tag_pattern is None:
-            tag_pattern = self.config.get('tag-pattern', '')
-            if not isinstance(tag_pattern, str):
+            from setuptools_scm import _config
+            tag_pattern = self.config.get('tag-pattern', _config.DEFAULT_TAG_REGEX)
+            if not isinstance(tag_pattern, (str, re.Pattern)):
                 raise TypeError('option `tag-pattern` must be a string')
 
             self.__config_tag_pattern = tag_pattern