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

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https://hg.mozilla.org/integration/gaia-1_4/rev/62bff9323471
Author: Luke Chang <lchang@mozilla.com>
Desc: Merge pull request #18401 from luke-chang/987496_v1.3t_hindi_input_method

Bug 987496 - Adding Hindi Input Method for B2G (v1.3t), r=rudylu
Bumping manifests a=b2g-bump