Bump @redocly/cli from 1.19.0 to 1.21.0

Bumps [@redocly/cli](https://github.com/Redocly/redocly-cli) from 1.19.0 to 1.21.0.
- [Release notes](https://github.com/Redocly/redocly-cli/releases)
- [Changelog](https://github.com/Redocly/redocly-cli/blob/main/docs/changelog.md)
- [Commits](https://github.com/Redocly/redocly-cli/compare/@redocly/cli@1.19.0...@redocly/cli@1.21.0)

---
updated-dependencies:
- dependency-name: "@redocly/cli"
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

package.json

@@ -12,7 +12,7 @@
   "license": "GPL-3.0-only",
   "description": "",
   "devDependencies": {
-    "@redocly/cli": "^1.19.0",
+    "@redocly/cli": "^1.21.0",
     "@types/better-sqlite3": "^7.6.11",
     "@types/node": "^22.4.1",
     "typescript": "^5.5.4"