update scaffolding and async versions

Author: jamesfredley

gradle.properties

@@ -38,7 +38,7 @@ converters.version=6.0.0-SNAPSHOT
 directory-watcher.version=0.18.0
 flying-saucer-pdf-openpdf.version=9.4.0
 geb-spock.version=7.0
-grails-async.version=6.0.0-SNAPSHOT
+grails-async.version=6.0.0-M2
 grails-datastore.version=9.0.0-SNAPSHOT
 grails-datastore-gorm-hibernate5.version=9.0.0-SNAPSHOT
 grails-datastore-gorm-mongodb.version=9.0.0-SNAPSHOT

grails-bom/plugins.properties

@@ -7,7 +7,7 @@ mongodb=9.0.0-SNAPSHOT
 neo4j=8.1.0
 rxjava=1.1.1
 rxjava2=2.0.0
-scaffolding=6.0.0-SNAPSHOT
+scaffolding=6.0.0-M1
 views-gradle=4.0.0-SNAPSHOT
 views-json=4.0.0-SNAPSHOT
 views-json-templates=4.0.0-SNAPSHOT