Bumping gaia.json for 1 gaia revision(s) a=gaia-bump

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https://hg.mozilla.org/integration/gaia-2_0/rev/b6bdb08f0fbc
Author: Jonathan Griffin <jgriffin@mozilla.com>
Desc: Merge pull request #20258 from jonallengriffin/bug1023001

Bug 1023001 - Use * as maxVersion for b2gdesktop extensions, a=RyanVM
Bumping manifests a=b2g-bump