Remove version from ant-run plugin

No need as picked up from the parent.

Author: Phillip Webb

spring-boot-starters/spring-boot-starter-parent/pom.xml

@@ -107,7 +107,6 @@
 				<plugin>
 					<groupId>org.apache.maven.plugins</groupId>
 					<artifactId>maven-antrun-plugin</artifactId>
-					<version>1.7</version>
 				</plugin>
 				<plugin>
 					<groupId>org.codehaus.mojo</groupId>