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

========

https://hg.mozilla.org/integration/gaia-2_1/rev/e673e3c4c8b0
Author: Wil Clouser <clouserw@gmail.com>
Desc: Merge pull request #26205 from clouserw/1083528.1

Bug 1083528 - Add dev/stage Marketplaces to 2.1  r=fabrice

========

https://hg.mozilla.org/integration/gaia-2_1/rev/b55fc894a34f
Author: Wil Clouser <clouserw@gmail.com>
Desc: Bug 1083528 - Add dev/stage Marketplaces to 2.1
Bumping manifests a=b2g-bump