[recipes] Add an OS X screenshot

[Matthias Clasen <matthiasc src gnome org>]

commit 6b70c29b0d004af9445f7b6f4288ca5f4c540751
Author: Matthias Clasen <mclasen redhat com>
Date:   Thu May 11 14:01:53 2017 -0400

    Add an OS X screenshot
    
    I want to link to this from the wiki.

 data/appdata/osx.png |  Bin 0 -> 6022831 bytes
 1 files changed, 0 insertions(+), 0 deletions(-)
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diff --git a/data/appdata/osx.png b/data/appdata/osx.png
new file mode 100644
index 0000000..685a5fd
Binary files /dev/null and b/data/appdata/osx.png differ