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

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https://hg.mozilla.org/integration/gaia-central/rev/20b8eee32bf7
Author: Arthur Chen <crh0716@gmail.com>
Desc: Merge pull request #15580 from crh0716/959971

Bug 959971 - Allows -1 as a valid retry count r=evelyn

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https://hg.mozilla.org/integration/gaia-central/rev/f8087f7756bb
Author: Arthur Chen <crh0716@gmail.com>
Desc: Bug 959971 - Allows -1 as a valid retry count

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https://hg.mozilla.org/integration/gaia-central/rev/487e96838245
Author: Arthur Chen <crh0716@gmail.com>
Desc: Merge pull request #15588 from crh0716/944601

Bug 944601 - Use getCardLockRetryCount properly r=evelyn

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https://hg.mozilla.org/integration/gaia-central/rev/5d6825176677
Author: Arthur Chen <crh0716@gmail.com>
Desc: Bug 944601 - Use getCardLockRetryCount properly
Bumping manifests a=b2g-bump