Update CHANGES.md: added info about gap-system#4258

Co-authored-by: Max Horn <max@quendi.de>

CHANGES.md

@@ -112,6 +112,7 @@ The label "release notes: added" has already been attached to them.
 ### Fixes/improvements in the experimental way to allow 3rd party code to link GAP as a library (libgap)
 
 - [#4081](https://github.com/gap-system/gap/pull/4081) Enhance `GAP_ValueGlobalVariable` to supported automatic variables (see `DeclareAutoreadableVariables`)
+- [#4258](https://github.com/gap-system/gap/pull/4258) Fixed `GAP_Enter` macro so that GAP's recursion depth counter is saved/restored. Without this, if too many GAP errors occurred during runtime a segmentation fault could occur in the program using libgap
 
 ### Fixes and improvements for the **Julia** integration