add release notes for 2.0.6 (#752)
add release notes for 2.0.6 (#752)


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