Bumping gaia.json for 2 gaia revision(s) a=gaia-bump

========

https://hg.mozilla.org/integration/gaia-central/rev/e92213819581
Author: Amir Nissim <amirnissim@gmail.com>
Desc: Merge pull request #17812 from EverythingMe/989731-icon-size

Bug 989731 - [E.me] Web app icon sizes and shadow are inconsistent

========

https://hg.mozilla.org/integration/gaia-central/rev/881138c4505d
Author: Amir Nissim <amirnissim@gmail.com>
Desc: Bug 989731 - [E.me] Web app icon sizes and shadow are inconsistent [r=ranbena]
Bumping manifests a=b2g-bump