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

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https://hg.mozilla.org/integration/gaia-central/rev/a1fdb2360e0b
Author: George <georgeiscoming@gmail.com>
Desc: Merge pull request #20221 from cctuan/1010095

Bug 1010095 - [Build] extract |getImagePathByResolution| and |isExcludedFromZip| from webapp-zip to another rule |post-process|

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https://hg.mozilla.org/integration/gaia-central/rev/afcb0976b9a6
Author: cctuan <georgeiscoming@gmail.com>
Desc: Bug 1010095 - [Build] extract |getImagePathByResolution| and |isExcludedFromZip| from webapp-zip to another rule |post-process|
Bumping manifests a=b2g-bump