TST: bump tolerance on TestHyp2f1.test_region3[hyp2f1_test_case23] (scipy#22364)

Author: j-bowhay

scipy/special/tests/test_hyp2f1.py

@@ -1135,7 +1135,7 @@ def test_region2(self, hyp2f1_test_case):
                     c=8.5,
                     z=(0.7368421052631575+0.5263157894736841j),
                     expected=(6.468457061368628+24.190040684917374j),
-                    rtol=5e-16,
+                    rtol=6e-16,
                 ),
             ),
             pytest.param(