Document Qt Wayland license changes in 5.13

Fixes: QTBUG-73919
Change-Id: I0a8524639b311288483a92a248ced9f0c3e7b8fb
Reviewed-by: Paul Olav Tvete <paul.tvete@qt.io>

doc/src/legal/licensechanges.qdoc

@@ -45,6 +45,19 @@
 
     The \l{libdus-1 headers} got updated to upstream version 1.12.12.
 
+    \section2 Qt Wayland
+
+    \list
+        \li The fullscreen-shell-unstable-v1 version 1 was added under the MIT
+        License.
+        \li The linux-dmabuf-unstable-v1 protocol version 3 was added under the
+        MIT License.
+        \li The wayland protocol got updated to version 1.16.0.
+        \li The wl-scaler protocol version 2 was added under the MIT License.
+        \li The wp-viewporter protocol version 1 was added under the MIT
+        License.
+    \endlist
+
     \section1 Qt 5.12.3
 
     \section2 Qt GUI Module