Update BOM - Grails Gradle Plugin 6.0.0

Author: puneetbehl

grails-bom/plugins.properties

@@ -1,7 +1,7 @@
 gorm.hibernate5=8.0.0
 gorm.mongodb=8.0.0
 gorm.neo4j=8.0.0
-grails-gradle-plugin=6.0.0-RC1
+grails-gradle-plugin=6.0.0
 cache=5.0.1
 rxjava=1.1.1
 rxjava2=2.0.0