Upgrade to Dependency Management Plugin 0.5.6.RELEASE

Closes gh-5211

Author: wilkinsona

spring-boot-parent/pom.xml

@@ -50,7 +50,7 @@
 			<dependency>
 				<groupId>io.spring.gradle</groupId>
 				<artifactId>dependency-management-plugin</artifactId>
-				<version>0.5.4.RELEASE</version>
+				<version>0.5.6.RELEASE</version>
 			</dependency>
 			<dependency>
 				<groupId>jline</groupId>