Allow static import of repackaged Spring REST Docs REST Assured integration

[wilkinsona]

Spring REST Docs 3 is going to remove the version number from the org.springframework.restdocs.restassured3 package so it becomes org.springframework.restdocs.restassured instead. I'd like to allow static imports of classes within org.springframework.restdocs.restassured while also retaining org.springframework.restdocs.restassured3 for backwards compatibility.