Add gmavenplus-plugin to parent POM

spring-boot-docs/pom.xml

@@ -176,7 +176,6 @@
 					<plugin>
 						<groupId>org.codehaus.gmavenplus</groupId>
 						<artifactId>gmavenplus-plugin</artifactId>
-						<version>1.2</version>
 						<executions>
 							<execution>
 								<goals>

spring-boot-parent/pom.xml

@@ -272,6 +272,11 @@
 					<artifactId>maven-site-plugin</artifactId>
 					<version>3.3</version>
 				</plugin>
+				<plugin>
+					<groupId>org.codehaus.gmavenplus</groupId>
+					<artifactId>gmavenplus-plugin</artifactId>
+					<version>1.2</version>
+				</plugin>
 				<plugin>
 					<groupId>org.codehaus.mojo</groupId>
 					<artifactId>sonar-maven-plugin</artifactId>