Only stat the .dockerenv file once (#76097)

homeassistant/util/package.py

@@ -2,6 +2,7 @@
 from __future__ import annotations
 
 import asyncio
+from functools import cache
 from importlib.metadata import PackageNotFoundError, version
 import logging
 import os
@@ -23,6 +24,7 @@ def is_virtual_env() -> bool:
     )
 
 
+@cache
 def is_docker_env() -> bool:
     """Return True if we run in a docker env."""
     return Path("/.dockerenv").exists()