fix(deps): update dependency keycloak-js to v21

This MR contains the following updates:

Package	Type	Update	Change
keycloak-js (source)	dependencies	major	^20.0.1 -> ^21.0.0

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Release Notes

keycloak/keycloak

v21.0.0

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packages/auth/package.json

@@ -43,7 +43,7 @@
         "@dbp-toolkit/common": "^0.3.3",
         "@open-wc/scoped-elements": "^2.1.0",
         "event-target-shim": "^6.0.0",
-        "keycloak-js": "^20.0.1",
+        "keycloak-js": "^21.0.0",
         "lit": "^2.0.0"
     },
     "scripts": {