xfce4-whiskermenu-plugin: update to 2.7.0

Change log:

2.7.0
=====
- Add showing categories as icons on top or bottom. (Issue #62)
- Add hiding username. (Issue #36)
- Add rounded profile picture.
- Add optional AccountsService support.
- Add catfish search action.
- Add CSS classes for theming.
- Improve search result relevance.
- Make stripping release builds optional.
- Rearrange settings dialog.
- Remove sliding out search results.
- Remove useless grab check.
- Rename icon to follow reverse DNS scheme.
- Replace size grip with resizing from edges.
- Replace slots with lambdas.
- Use original menu layout.
- Use dm-tool for switching users.
- Translation updates: Basque, Bulgarian, Chinese (Taiwan), Danish, Dutch,
  French, Greek, Lithuanian, Portuguese, Portuguese (Brazil), Slovak,
  Spanish, Swedish, Turkish, Ukrainian.

2.6.2
=====
- Fix background shifting when showing menu. (Issue #41)
- Fix menu not toggling after pressing escape. (Issue #65)
- Properly prevent interactive search in treeview.

2.6.1
=====
- Fix menu not toggling. (Issue #61)
- Fix small icon in multi-row panels. (Issue #37)
- Fix missing minimize and maximize buttons in settings dialog.
- Replace deprecated code for grab check.
- Translation updates: Greek, Slovak, Spanish.

2.6.0
=====
- Fix unable to resize with metacity. (Issue #56)
- Fix invalid desktop files when hiding applications. (Issue #53)
- Fix not showing focused launcher when searching. (Issue #45)
- Add option to disable sorting categories. (Issue #42)
- Translation updates: Arabic, Basque, Bulgarian, Catalan, Chinese (China),
  Chinese (Taiwan), Czech, Danish, Dutch, Esperanto, Finnish, French,
  Galician, Georgian, German, Hungarian, Interlingue, Italian, Lithuanian,
  Polish, Portuguese, Portuguese (Brazil), Russian, Spanish, Swedish, Thai,
  Turkish, Ukrainian.

(gutteridge)