Log Message:
mate-netbook: update to 1.26.0

Change log:

### mate-netbook 1.26.0

  * Translations update
  * update copyright to 2021
  * mate-window-picker-applet: Do not build the path to the menu file
  * mate-maximus-autostart.desktop: The Encoding key is deprecated
  * mate-window: Replace GtkStock icons
  * Update copyright to 2021
  * Remove USE_MATE2_MACROS from autogen.sh (legacy)
  * build: silent build warnings for distcheck
  * windows-picker: fix `make clean` command
  * use MATE_COMPILE_WARNINGS from mate-common