GROOVY-10332: Bump logback to 1.2.6
GROOVY-10332: Bump logback to 1.2.6

paulk-asert/groovy,apache/groovy,paulk-asert/groovy,apache/groovy,paulk-asert/groovy,apache/incubator-groovy,apache/incubator-groovy,apache/incubator-groovy,apache/groovy,paulk-asert/groovy,apache/incubator-groovy,apache/groovy