Doc Pom plugins update (#1259)
Doc Pom plugins update (#1259)

removed old docs pom plugins for docbook. using new ones in common with other Spring cloud projects.


spring-cloud/spring-cloud-gcp,GoogleCloudPlatform/spring-cloud-gcp,GoogleCloudPlatform/spring-cloud-gcp,GoogleCloudPlatform/spring-cloud-gcp,spring-cloud/spring-cloud-gcp,spring-cloud/spring-cloud-gcp,GoogleCloudPlatform/spring-cloud-gcp,spring-cloud/spring-cloud-gcp,GoogleCloudPlatform/spring-cloud-gcp