dev-python/manhole: update PYTHON_COMPAT for 3.12

Signed-off-by: Henri Gasc <gasc@eurecom.fr>

dev-python/manhole/files/importlib.patch

@@ -0,0 +1,11 @@
+Use importlib as imp is removed in python3.12
+--- a/tests/test_manhole.py
++++ b/tests/test_manhole.py
+@@ -1,6 +1,6 @@
+ from __future__ import print_function
+ 
+-import imp
++import importlib
+ import os
+ import re
+ import select