Link to the new Microsoft patent license.

This applies in addition to the earlier grant made by
Skype, which was purchased by Microsoft.
diff --git a/COPYING b/COPYING
index 3167a00..f4159e6 100644
--- a/COPYING
+++ b/COPYING
@@ -37,8 +37,8 @@
 Xiph.Org Foundation:
 https://datatracker.ietf.org/ipr/1524/
 
-Skype Limited:
-https://datatracker.ietf.org/ipr/1602/
+Microsoft Corporation:
+https://datatracker.ietf.org/ipr/1914/
 
 Broadcom Corporation:
 https://datatracker.ietf.org/ipr/1526/