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

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https://hg.mozilla.org/integration/gaia-2_1/rev/d6a3dc61e5fd
Author: EragonJ (E.J.) <eragonj@eragonj.me>
Desc: Merge pull request #26273 from EragonJ/v2.1-bug-1086686

Bug 1086686 - [2.1][l10n][Settings] Basque: The USB button header text

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https://hg.mozilla.org/integration/gaia-2_1/rev/3a5a7b38227e
Author: EragonJ <eragonj@eragonj.me>
Desc: Bug 1086686 - [2.1][l10n][Settings] Basque: The USB button header text
Bumping manifests a=b2g-bump