Support refresh token revocation

[luckpoint]

Changes

This PR adds a new revoke() method to the Auth0Client class that allows applications to revoke refresh tokens using the OAuth 2.0 revocation endpoint.

Classes and methods added:

• Added revoke() method to Auth0Client class
• Added revokeToken() function to api.ts module

Key features:

• Revokes refresh tokens via the /oauth/revoke endpoint
• Updates cache to remove the revoked refresh token after successful revocation
• Does nothing if useRefreshTokens is disabled or no refresh token is found

Usage example:

// Revoke the refresh token for default audience/scope
await auth0.revoke();

// Revoke refresh token for specific audience/scope
await auth0.revoke({
  authorizationParams: {
    audience: 'https://api.example.com',
    scope: 'read:users'
  }
});

### Testing

I've updated the Quickstart to enable testing of the revoke() function.
https://github.com/luckpoint/auth0-javascript-samples/tree/feature/add-revoke-method

- [x] This change adds unit test coverage
- [x] This change adds integration test coverage
- [x] This change has been tested on the latest version of the platform/language

### Checklist

- [x] I have read the [Auth0 general contribution guidelines](https://github.com/auth0/open-source-template/blob/master/GENERAL-CONTRIBUTING.md)
- [x ] I have read the [Auth0 Code of Conduct](https://github.com/auth0/open-source-template/blob/master/CODE-OF-CONDUCT.md)
- [x] All code quality tools/guidelines have been run/followed