Update MS-SSIM header (#231)

neuralcompression/functional/_multiscale_structural_similarity.py

@@ -1,3 +1,8 @@
+# Copyright (c) Meta Platforms, Inc. and affiliates.
+#
+# This source code is licensed under the MIT license found in the
+# LICENSE file in the root directory of this source tree.
+
 from typing import Callable, Optional, Sequence
 
 import torch