Add postfixOps

Author: style95

tests/src/test/scala/org/apache/openwhisk/core/scheduler/queue/test/ElasticSearchDurationCheckerTests.scala

@@ -41,6 +41,7 @@ import pureconfig.generic.auto._
 import pureconfig.loadConfigOrThrow
 import java.time.Instant
 import java.time.temporal.ChronoUnit
+import scala.language.postfixOps
 
 import scala.collection.mutable
 import scala.concurrent.ExecutionContextExecutor