Fetch extensions from kubeconfig with get

Using get with default is prefered over checking dict keys manually

Author: Lillecarl

kr8s/_config.py

@@ -350,4 +350,4 @@ def contexts(self) -> list[dict]:
 
     @property
     def extensions(self) -> list[dict]:
-        return self._raw["extensions"] if "extensions" in self._raw else []
+        return self._raw.get("extensions", [])