Update changes file for 5.12.10

Change-Id: I01d63f447647c46fecf8df14c8c4df21189fd594
Reviewed-by: Allan Sandfeld Jensen <[email protected]>
(cherry picked from commit 457c8ba)
Reviewed-by: Qt Cherry-pick Bot <[email protected]>

Author: mibrunin

dist/changes-5.12.10

@@ -27,6 +27,7 @@ General
   - [QTBUG-75391] Fix pasting Unicode characters copied from WebEngine on macOS
   - [QTBUG-83710] Fix input of keys requiring AltGr on Windows
   - [QTBUG-84337] Fixed GPU switching with CoreProfile on macOS (for e.g. AirPlay)
+  - [QTBUG-86018] Fixed build with Bison 3.7
   - Fixed build with the linux-clang 10 spec
 
 Chromium