Update dependency org.grails:grails-core to v6.0.0

Author: renovate[bot]

gradle.properties

@@ -13,7 +13,7 @@ jaxbVersion=2.3.1
 junitJupiterVersion=5.9.3
 picocliVersion=4.6.3
 projectVersion=8.0.1-SNAPSHOT
-pluginGrailsVersion=6.0.0-RC1
+pluginGrailsVersion=6.0.0
 seleniumSafariDriverVersion=3.14.0
 seleniumVersion=3.14.0
 servletApiVersion=4.0.1
@@ -27,7 +27,7 @@ tomcatVersion=9.0.78
 
 # Following are used only for example projects
 fieldsVersion=3.0.0.RC1
-grailsVersion=6.0.0-SNAPSHOT
+grailsVersion=6.0.0
 micrometer.version=1.8.0
 scaffoldingVersion=4.1.0
 testingSupportVersion=3.0.0