keycloak: update quay.io/keycloak/keycloak Docker tag to v26.4.2

Author: renovate[bot]

keycloak/kustomization.yaml

@@ -22,4 +22,4 @@ generators:
   - secret-generator.yaml
 images:
   - name: quay.io/keycloak/keycloak
-    newTag: 26.3.2@sha256:98fab020a3a490aba0978f237e2a06cd0ea42bf149c6cf10f11c0aaf27728ff2
+    newTag: 26.4.2@sha256:3617b09bb4b7510a8d8d9b9fc5707399e2d70688dbcc2f8fb013a144829be1b9