Log Message:
Update xfce4-screenshooter to 1.8.99:

=== Version 1.8.99 ===

  * Enhancements:
    - Port to GTK+3
    - Updated translations (thanks to translators!)

  * Bugs fixed:
    - Fix appdata description
    - Fix crash in GValueArray handling (bug #11879)
    - Use while instead of when in strings (bug #12157)
    - Fix gray overlay in region mode screenshots (bug #11922)
    - Fix crash when uploading to zimagez (bug #11879)