chore: fix ionos link

Author: xeniape

modules/ROOT/pages/kubernetes/ionos-managed-stackable.adoc

@@ -1,5 +1,5 @@
 = IONOS managed Stackable
 
-https://cloud.ionos.com/solutions/managed-stackable
+https://cloud.ionos.com/managed/managed-stackable[https://cloud.ionos.com/managed/managed-stackable{external-link-icon}^]
 
 > The Managed Stackable Data Platform from IONOS Cloud is designed to enable you to work with maximum efficiency: Simply select the appropriate data management tools for your respective purpose, build individual stacks for yourself or your customers and make all your data productively usable as quickly as possible