libhandy: upgrade 1.4.0 -> 1.5.0

=============
Version 1.5.0
=============

- Introduce HdyStyleManager for managing color schemes (light/dark) and
  high contrast mode.
  - Support the cross-platform color scheme preference in the
    settings portal.
- HdyPreferencesPage
  - Remove adaptive margins to fix default window sizes
- HdyTabBar
  - Handle middle click on button release rather than press
- Various memory leak fixes
- Translation updates:
  - Brazilian Portuguese
  - Finnish
  - Indonesian
  - Portuguese
  - Serbian
  - Swedish
  - Ukrainian

Signed-off-by: Wang Mingyu <wangmy@fujitsu.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>