You need to manually import the ServerHttpSecurity invoke.
import org.springframework.security.config.web.server.invoke
/
import org.springframework.security.config.annotation.web.invoke
S. Gulwani, and M. Marron. Proceedings of the 2014 ACM SIGMOD International Conference on Management of Data, page 803--814. New York, NY, USA, ACM, (2014)