Update README.md

Author: peppelinux

README.md

@@ -29,6 +29,7 @@ It also comes with the following `add_on` modules.
 
 * Custom scopes, that extends [OIDC standard ScopeClaims](https://openid.net/specs/openid-connect-core-1_0.html#ScopeClaims)
 * [Proof Key for Code Exchange by OAuth Public Clients (PKCE)](https://tools.ietf.org/html/rfc7636)
+* [OAuth2 PAR](https://datatracker.ietf.org/doc/html/rfc9126)
 * [OAuth2 RAR](https://datatracker.ietf.org/doc/html/draft-ietf-oauth-rar)
 * [OAuth2 DPoP](https://tools.ietf.org/id/draft-fett-oauth-dpop-04.html)