Bumping gaia.json for 1 gaia-1_3 revision(s) a=gaia-bump

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https://hg.mozilla.org/integration/gaia-1_3/rev/306bef280cec
Author: vingtetun <21@vingtetun.org>
Desc: Merge pull request #15997 from vingtetun/bug967277

Bug 967277 - [Contacts] Scrolling the contacts app causes reflow. r=arct...