11
There is now a standard Grails database migration plugin available. According to this blog post at least the liquibase plugin will therefore not be maintained past the liquibase 1.9 release anymore.
The new database migration plugin has built-in functionality to execute changelogs on startup and supports the definition of changes in Groovy DSL, so it's probably what you are looking for.
I have heard that Autobase is still maintained, but consider that the Grails Database Migration Plugin is written by the core team, and likely going to be the officially supported one.
In other words, encourage you can wait on Grails 1.4 --> roadmap before choosing either of the plugins above.