Update the version of AutoValue mentioned in the top-level README.md from 1.2 to 1.3. This is https://github.com/google/auto/pull/428 by @peihe.
Update the version of AutoValue mentioned in the top-level README.md from 1.2 to 1.3. This is https://github.com/google/auto/pull/428 by @peihe.

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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=145857789

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