Remove unnecessary override of helper plugin's version

Author: wilkinsona

spring-boot-project/spring-boot-tools/spring-boot-gradle-plugin/pom.xml

@@ -89,7 +89,6 @@
 			<plugin>
 				<groupId>org.codehaus.mojo</groupId>
 				<artifactId>build-helper-maven-plugin</artifactId>
-				<version>1.12</version>
 				<executions>
 					<execution>
 						<id>attach-artifacts</id>