[sushi] Created tag 3.28.0

[Cosimo Cecchi <cosimoc src gnome org>]

The unsigned tag '3.28.0' was created.

Tagger: Cosimo Cecchi <cosimo endlessm com>
Date: Wed Apr 18 18:41:53 2018 -0700

    Release 3.28.0

Changes since the last tag '3.24.0':

Cosimo Cecchi (2):
      build: remove unoconv leftover
      release: prepare for 3.28.0

GNOME Translation Robot (1):
      Update Scottish Gaelic translation

Pawan Chitrakar (1):
      Add Nepali translation

Pieter Schalk Schoeman (1):
      Add Afrikaans translation

Princeton Ferro (1):
      image: add support for GIF animations

Robert McQueen (4):
      src/js/viewers/evince.js: add docx/pptx/xlsx MIME types
      sushi-pdf-loader: switch from shell command parsing to a static argv
      sushi-pdf-loader: port from unoconv to libreoffice --convert-to pdf
      sushi-pdf-loader: run LibreOffice through flatpak if available

Xavi Ivars (1):
      [l10n] Updated Catalan (Valencian) translation