fixes spring-cloud/spring-cloud-task#8

SCT-8: Added NoOpTaskExplorer

Set the Junit to test scope.

spring-cloud-task-core/pom.xml

@@ -18,6 +18,11 @@
 	<description>Spring Cloud Task</description>
 
 	<dependencies>
+		<dependency>
+			<groupId>junit</groupId>
+			<artifactId>junit</artifactId>
+			<scope>test</scope>
+		</dependency>
 		<dependency>
 			<groupId>org.springframework.boot</groupId>
 			<artifactId>spring-boot-starter-aop</artifactId>