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

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https://hg.mozilla.org/integration/gaia-central/rev/028654528b0c
Author: Casey Yee <cyee@mozilla.com>
Desc: Merge pull request #14114 from caseyyee/bug-943010

Bug 943010 - [Email] Update to the orange 1.3 header

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https://hg.mozilla.org/integration/gaia-central/rev/5ebb9dc181e8
Author: Casey Yee <casey@caseyyee.com>
Desc: Bug 943010 - [Email] Update to the orange 1.3 header

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https://hg.mozilla.org/integration/gaia-central/rev/55f3215d4b5d
Author: Casey Yee <cyee@mozilla.com>
Desc: Merge pull request #14029 from caseyyee/bug-943000

Bug 943000: Update to Dark 1.3 Header

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https://hg.mozilla.org/integration/gaia-central/rev/7111a79a206e
Author: Casey Yee <casey@caseyyee.com>
Desc: Bug 943000: Update to Dark 1.3 Header