make sure tests is the optimal vq bridge

Author: lucidrains

tests/test_readme.py

@@ -512,6 +512,7 @@ def test_fvq():
     from x_transformers import ContinuousTransformerWrapper, Encoder
 
     vq_bridge = ContinuousTransformerWrapper(
+        num_memory_tokens = 2,
         attn_layers = Encoder(
             dim = 256,
             depth = 1,