Bump rollup from 4.20.0 to 4.21.0 (keycloak#32221)

Bumps [rollup](https://github.com/rollup/rollup) from 4.20.0 to 4.21.0.
- [Release notes](https://github.com/rollup/rollup/releases)
- [Changelog](https://github.com/rollup/rollup/blob/master/CHANGELOG.md)
- [Commits](rollup/rollup@v4.20.0...v4.21.0)

---
updated-dependencies:
- dependency-name: rollup
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

js/libs/keycloak-js/package.json

@@ -74,7 +74,7 @@
     "@rollup/plugin-terser": "^0.4.4",
     "@rollup/plugin-typescript": "^11.1.6",
     "es6-promise": "^4.2.8",
-    "rollup": "^4.20.0",
+    "rollup": "^4.21.0",
     "shx": "^0.3.4"
   },
   "dependencies": {