Merge pull request #581 from medizininformatik-initiative/renovate/keycloak-keycloak-26.x

Update keycloak/keycloak Docker tag to v26.3

Author: michael-82

.github/integration-test/docker-compose.yml

@@ -135,7 +135,7 @@ services:
       - "dataportal-auth-db:/var/lib/postgresql/data"
 
   auth:
-    image: keycloak/keycloak:26.2
+    image: keycloak/keycloak:26.3
     command: ["start", "--import-realm"]
     restart: unless-stopped
     environment: