Update unittest tags

Author: fangerer

graalpython/com.oracle.graal.python.test/src/tests/unittest_tags/test_contextlib.txt

@@ -5,6 +5,7 @@
 *graalpython.lib-python.3.test.test_contextlib.ContextManagerTestCase.test_contextmanager_do_not_unchain_non_stopiteration_exceptions
 *graalpython.lib-python.3.test.test_contextlib.ContextManagerTestCase.test_contextmanager_doc_attrib
 *graalpython.lib-python.3.test.test_contextlib.ContextManagerTestCase.test_contextmanager_except
+*graalpython.lib-python.3.test.test_contextlib.ContextManagerTestCase.test_contextmanager_except_pep479
 *graalpython.lib-python.3.test.test_contextlib.ContextManagerTestCase.test_contextmanager_except_stopiter
 *graalpython.lib-python.3.test.test_contextlib.ContextManagerTestCase.test_contextmanager_finally
 *graalpython.lib-python.3.test.test_contextlib.ContextManagerTestCase.test_contextmanager_no_reraise