Add information about the fixed GTK assertion errors to CHANGES
2.0 unreleased
=====================
+Notable changes and features
+----------------------------
+
+Notable bugfixes
+----------------------------
+- GUIs: Patches to GTK assertion errors on (mostly) non-Ubuntu systems.
+ Fixes Github issue #140. Thanks to Sarah Clark.
+
+
+
1.25 June 2022
=====================
