[gnome-software] Created tag 3.26.6

[Kalev Lember <klember src gnome org>]

The signed tag '3.26.6' was created.

Tagger: Kalev Lember <klember redhat com>
Date: 1518091896 +0100

    ==== Version 3.26.6 ====

Changes since the last tag '3.26.5':

Balló György (1):
      Fix build when gtkspell enabled

Joaquim Rocha (1):
      trivial: Fix leak in the external-appstream plugin

Kalev Lember (24):
      trivial: Post release version bump
      steam: Fix an out of bounds read
      plugin loader: Fix a crash in gs_plugin_loader_helper_free
      trivial: Fix a typo
      overview page: Remove old recommended categories before adding new
      screenshot image: Fix a memory leak when loading multiple times
      app-row: Put descriptions in a separate size group
      details page: Hide fallback screenshot for fonts that have screenshots
      Revert "packagekit: Implement repository enabling"
      overview page: Sync popular apps error path with recent apps
      overview page: Pre-seed recent app tiles to make first load seamless
      details page: Hide 'Updated' field for plugins that don't set that
      packagekit history: Only process apps managed by the packagekit plugin
      packagekit: Set description from package details when refining
      packagekit: Fix what-provides search to correctly handle installed packages
      plugin loader: Slightly increase warning timeouts
      Remove use of deprecated gdk_keymap_get_default() API
      shell: Fix a memory leak when dismissing events
      trivial: application: Remove an unused field
      packagekit history: Fix a leak on the error path
      packagekit: Never call GetDetails when there are no source IDs
      sources dialog: Sync with master
      Disable third party repo infobar on overview page
      Release version 3.26.6

Marek Cernocky (1):
      Updated Czech translation

Pieter Schalk Schoeman (1):
      Update Afrikaans translation

Robert Ancell (2):
      Fix crash when no plugin performs purchase
      Prompt for auth when app purchasing requires it