Update versions of Truth and Guava in Maven build.
Update versions of Truth and Guava in Maven build.

Fixes #405

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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=280302646

cushon/google-java-format,sormuras/google-java-format,cushon/google-java-format,sormuras/google-java-format,sormuras/google-java-format,cushon/google-java-format