fix: loosen constructor str rejection test for PyPy compatibility

PyPy doesn't support tp_vectorcall, so constructors fall back to
tp_init with y* format, which gives a different error message.
Use plain assertRaises(TypeError) instead of assertRaisesRegex.

Author: ifduyue

tests/test_hashlib_compat.py

@@ -30,8 +30,7 @@ def test_str_rejected(self):
     def test_str_rejected_constructor(self):
         for algo in ('xxh32', 'xxh64', 'xxh3_64', 'xxh3_128'):
             cls = getattr(xxhash, algo)
-            with self.assertRaisesRegex(TypeError,
-                    'Strings must be encoded before hashing'):
+            with self.assertRaises(TypeError):
                 cls('hello')
 
     def test_str_rejected_update(self):