Fix dead spring cloud docs link (#3660)

Author: ulischulte

spring-boot-admin-docs/src/site/asciidoc/getting-started.adoc

@@ -48,7 +48,7 @@ NOTE: See also the {github-src}/spring-boot-admin-samples/spring-boot-admin-samp
 [[register-client-applications]]
 == Registering Client Applications ==
 
-To register your application at the SBA Server, you can either include the SBA Client or use http://projects.spring.io/spring-cloud/spring-cloud.html[Spring Cloud Discovery] (e.g. Eureka, Consul, ...). There is also a <<server#spring-cloud-discovery-static-config,simple option using a static configuration on the SBA Server side>>.
+To register your application at the SBA Server, you can either include the SBA Client or use https://spring.io/projects/spring-cloud[Spring Cloud Discovery] (e.g. Eureka, Consul, ...). There is also a <<server#spring-cloud-discovery-static-config,simple option using a static configuration on the SBA Server side>>.
 
 [[register-clients-via-spring-boot-admin]]
 === Spring Boot Admin Client ===