FIX: Use all keras optimizers

Author: seanpmorgan

tensorflow_addons/layers/wrappers_test.py

@@ -66,7 +66,7 @@ def test_weightnorm_conv2d(self):
 
         model.add(tf.keras.layers.Activation('relu'))
         model.compile(
-            optimizer=tf.optimizers.RMSprop(learning_rate=0.001), loss='mse')
+            optimizer=tf.keras.optimizers.RMSprop(learning_rate=0.001), loss='mse')
         model.fit(
             np.random.random((2, 4, 4, 3)),
             np.random.random((2, 4, 4, 5)),

tensorflow_addons/optimizers/weight_decay_optimizers_test.py

@@ -269,7 +269,7 @@ class ExtendWithWeightDecayTest(SGDWTest):
     """Verify that the factory function SGDW is the same as SGDW."""
 
     optimizer = weight_decay_optimizers.extend_with_decoupled_weight_decay(
-        tf.optimizers.SGD)
+        tf.keras.optimizers.SGD)
 
 
 if __name__ == "__main__":