You need to manually import the ServerHttpSecurity invoke.
import org.springframework.security.config.web.server.invoke
/
import org.springframework.security.config.annotation.web.invoke
H. Mühe, A. Angerer, A. Hoffmann, and W. Reif. 1st International Workshop on Domain-Specific Languages and models for ROBotic systems (DSLRob’10), 2010 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS 2010), (2010)