Switch from inspect.getargspec to inspect.getfullargspec

inspect.getargspec has been deprecated since 3.0

cherrypy/_cpdispatch.py

@@ -206,12 +206,8 @@ def test_callable_spec(callable, callable_args, callable_kwargs):
     def test_callable_spec(callable, args, kwargs):  # noqa: F811
         return None
 else:
-    getargspec = inspect.getargspec
-    # Python 3 requires using getfullargspec if
-    # keyword-only arguments are present
-    if hasattr(inspect, 'getfullargspec'):
-        def getargspec(callable):
-            return inspect.getfullargspec(callable)[:4]
+    def getargspec(callable):
+        return inspect.getfullargspec(callable)[:4]
 
 
 class LateParamPageHandler(PageHandler):