Update quay.io/keycloak/keycloak Docker tag to v26.1 (#419)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

services/backend/services/keycloak/compose.base.yaml

@@ -1,6 +1,6 @@
 services:
   keycloak:
-    image: quay.io/keycloak/keycloak:26.0
+    image: quay.io/keycloak/keycloak:26.1
     command: start-dev --import-realm --health-enabled=true --http-port=80
     env_file: ./config/.env
     volumes: