Error Prone 2.30.0

New checks:

• AutoValueBoxedValues: Detects unnecessary boxing in AutoValue classes.
• DefaultLocale: Detects implicit use of the JVM default locale, which can result in differing behaviour between JVM executions.
• UnnecessaryBreakInSwitch: Remove unnecessary break statements in -> switches.

Closed issues: #632, #4487

Full changelog: v2.29.2...v2.30.0