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

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https://hg.mozilla.org/integration/gaia-central/rev/4b140afdff45
Author: evanxd <itoyxd@gmail.com>
Desc: Merge pull request #24924 from evanxd/bug-1075455

Bug 1075455 - Sync present date on month view r=mmedeiros

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https://hg.mozilla.org/integration/gaia-central/rev/ad476fdcab3d
Author: Evan Xd <itoyxd@gmail.com>
Desc: Bug 1075455 - Sync present date on month view
Bumping manifests a=b2g-bump