This update for kwin5 fixes the following issues:

- Add patch to fix software rendering detection with Mesa 20.2+ (boo#1179845)

Update to 5.18.6

* New bugfix release
* For more details please see:
* https://kde.org/announcements/plasma-5.18.6

Changes since 5.18.5:

* x11: Make removal of X11 event filters safe (kde#423319)
* Fix invalidation of cached x stacking order in wayland only mode
* effects/slidingpopups: Properly clip windows
* Grab all possible keyboard modifiers for window commands (kde#424272)
* [x11] Hold a passive grab on buttons only when needed (kde#394772)
* Check if we successfully restored input focus
* Partially revert a0c4a8e766a2160 (kde#424223)
* [x11] Force FocusIn events for already focused windows
* [x11] Create egl scene textures with right size
* Fix the Plastik decoration with Qt 5.15
* [wayland] Fix misuse of EGL/eglmesaext.h (kde#422131)
* [wayland] Place lockscreen greeter above other windows
* [kcmkwin/kwindecoration] Don't exec() QDialog (kde#421053)

This update was imported from the openSUSE:Leap:15.2:Update update project.