CI: fix new ruff error B028

	B028 No explicit `stacklevel` keyword argument found

Caused by this recent addition to ruff:
	astral-sh/ruff#3550

codespell_lib/tests/test_dictionary.py

@@ -25,7 +25,8 @@
     else:
         warnings.warn(
             "aspell not found, but not required, skipping aspell tests. Got "
-            "error during import:\n{}".format(exp)
+            "error during import:\n{}".format(exp),
+            stacklevel=2,
         )
 
 global_err_dicts: Dict[str, Dict[str, Any]] = {}