You need to manually import the ServerHttpSecurity invoke.
import org.springframework.security.config.web.server.invoke
/
import org.springframework.security.config.annotation.web.invoke
K. Miksa, M. Kasztelnik, P. Sabina, and T. Walter. Models in Software Engineering, volume 6002 of Lecture Notes in Computer Science, Springer Berlin Heidelberg, (2010)