keycloak: update quay.io/keycloak/keycloak Docker tag to v26.2.1

Author: renovate[bot]

keycloak/kustomization.yaml

@@ -22,4 +22,4 @@ generators:
   - secret-generator.yaml
 images:
   - name: quay.io/keycloak/keycloak
-    newTag: 26.1.4@sha256:044a457e04987e1fff756be3d2fa325a4ef420fa356b7034ecc9f1b693c32761
+    newTag: 26.2.1@sha256:9869b88191392727f0be7301e53573cc39c13c9d9b9b08492c97d1ea40366eae