Bumping gaia.json for 4 gaia revision(s) a=gaia-bump

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https://hg.mozilla.org/integration/gaia-central/rev/45083e0d5853
Author: Kevin Grandon <kevingrandon@yahoo.com>
Desc: Merge pull request #23732 from KevinGrandon/bug_1062942_start_page_refinements

Bug 1062942 - [Browser Start Page] Visual tweaks to headers

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https://hg.mozilla.org/integration/gaia-central/rev/42e66f39bc60
Author: Kevin Grandon <kevingrandon@yahoo.com>
Desc: Bug 1062942 - [Browser Start Page] Visual tweaks to headers r=epang

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https://hg.mozilla.org/integration/gaia-central/rev/f62e9760334b
Author: Dietrich Ayala <autonome@gmail.com>
Desc: Merge pull request #23699 from autonome/1062532-updates-refactor

Bug 1062532 - minor refactor of Settings->About->Updates code (r=arthur)

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https://hg.mozilla.org/integration/gaia-central/rev/bcd9fa87743d
Author: Dietrich Ayala <autonome@gmail.com>
Desc: Bug 1062532 - minor refactor of Settings->About->Updates code (r=tbd)
Bumping manifests a=b2g-bump