Use badges for subproject release versions in Auto README
Use badges for subproject release versions in Auto README

Closes https://github.com/google/auto/pull/457

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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=150676604

MaTriXy/auto,eamonnmcmanus/auto,google/auto,eamonnmcmanus/auto,google/auto,eamonnmcmanus/auto,MaTriXy/auto,google/auto