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

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https://hg.mozilla.org/integration/gaia-1_3/rev/62e56dc59a14
Author: Anthony Ricaud <anthony@ricaud.me>
Desc: Merge pull request #15955 from Rik/inactive-group-after-finishing-call-966951

Bug 966951 - "Group Call" is inactive when received call is hung up r=etienne
Bumping manifests a=b2g-bump