[Merge] ~aleasto/update-notifier:update-notification into update-notifier:master

[Sebastien Bacher]

Review: Approve

Thanks for the work, let's land it now!
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https://code.launchpad.net/~aleasto/update-notifier/+git/update-notifier/+merge/487372
Your team Ubuntu Core Development Team is requested to review the proposed merge of ~aleasto/update-notifier:update-notification into update-notifier:master.