[Opus] Update to v1.2.1

third_party/opus/src/LICENSE_PLEASE_READ.txt

Index: third_party/opus/src/LICENSE_PLEASE_READ.txt
diff --git a/third_party/opus/src/LICENSE_PLEASE_READ.txt b/third_party/opus/src/LICENSE_PLEASE_READ.txt
new file mode 100644
index 0000000000000000000000000000000000000000..bc88efa6cb05789a6a6e697577ae6d8e5532e5df
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+++ b/third_party/opus/src/LICENSE_PLEASE_READ.txt
@@ -0,0 +1,22 @@
+Contributions to the collaboration shall not be considered confidential.
+
+Each contributor represents and warrants that it has the right and
+authority to license copyright in its contributions to the collaboration.
+
+Each contributor agrees to license the copyright in the contributions
+under the Modified (2-clause or 3-clause) BSD License or the Clear BSD License.
+
+Please see the IPR statements submitted to the IETF for the complete
+patent licensing details:
+
+Xiph.Org Foundation:
+https://datatracker.ietf.org/ipr/1524/
+
+Microsoft Corporation:
+https://datatracker.ietf.org/ipr/1914/
+
+Skype Limited:
+https://datatracker.ietf.org/ipr/1602/
+
+Broadcom Corporation:
+https://datatracker.ietf.org/ipr/1526/