Update quay.io/keycloak/keycloak Docker tag to v26

Signed-off-by: Renovate Bot <tech+renovate@vshn.ch>

Author: vshn-renovate

class/defaults.yml

@@ -44,7 +44,7 @@ parameters:
       keycloak:
         registry: quay.io
         repository: keycloak/keycloak
-        tag: 25.0.6
+        tag: 26.1.0
       busybox:
         registry: docker.io
         repository: busybox