sbt/notes/0.13.13/early.md

Fixes with compatibility implications

• sbt 0.13.13 renames the early command that was added in 0.13.1 to early(<command>). This fixes the regression #1041. For backward compatibility --error, --warn, --info, and --debug will continue to function during 0.13 series, but it is strongly encouraged to migrate to the single hyphen option: -error, -warn, -info, and -debug. @eed3si9n