Only compile regex pattern once

Improve the performance for creating the regexp pattern by caching them.
With this change they will be created on demand once and afterwards they
are used from the cache.

pontos/updateheader/updateheader.py

@@ -11,6 +11,7 @@
 import re
 import sys
 from dataclasses import dataclass
+from functools import cache
 from pathlib import Path
 from typing import Optional, Sequence, Union
 
@@ -282,11 +283,13 @@ def _get_exclude_list(
     return exclude_list
 
 
+@cache
 def _compile_outdated_regex() -> list[re.Pattern]:
     """prepare regex patterns to remove old copyright lines"""
     return [re.compile(rf"^(([#*]|//) ?)?{line}") for line in OLD_LINES]
 
 
+@cache
 def _compile_copyright_regex() -> re.Pattern:
     """prepare the copyright regex"""
     c_str = r"(SPDX-FileCopyrightText:|[Cc]opyright)"