xfce4-whiskermenu-plugin: update to 2.5.3

Change log:

2.5.3
=====
- Fix invalid command expansion with Xfce 4.14 (Issue #39)
- Translation updates: Basque, Portuguese (Brazil).

2.5.2
=====
- Do not reparent launched programs. (Issue #32)
- Translation updates: Basque, Danish, Greek.

2.5.1
=====
- Fix not always using new action icons. (Issue #33)

2.5.0
=====
- Add option to show all applications by default. (Issue #4)
- Rearrange sidebar buttons to match default category. (Issue #9)
- Show panel button title as tooltip in icon-only mode. (Issue #12)
- Always sort top-level categories.
- Vertically center contents of header.
- Use new Xfce action icons.
- Use new desktop ids for default programs.
- Rewrite to hide menu on focus out.
- Refactor code to use new Xfce functions.
- Refactor building translations.
- Translation updates: Bulgarian, Chinese (China), Chinese (Taiwan),
  Croatian, Czech, Danish, Dutch, Esperanto, French, Galician,
  German, Italian, Korean, Lithuanian, Malay, Polish, Portuguese,
  Portuguese (Brazil), Slovak, Spanish, Swedish, Turkish.

(gutteridge)