Update README.md (istio#49016)

* Update README.md

Added Ztunnel repo

* Update README.md

Co-authored-by: Eric Van Norman <[email protected]>

---------

Co-authored-by: Eric Van Norman <[email protected]>

Author: ymesika

README.md

@@ -95,6 +95,9 @@ including Citadel (acting as Certificate Authority), citadel agent, etc.
 extensions to the [Envoy proxy](https://github.com/envoyproxy/envoy) (in the form of
 Envoy filters) that support authentication, authorization, and telemetry collection.
 
+- [istio/ztunnel](https://github.com/istio/ztunnel). The repository contains the Rust implementation of the ztunnel
+component of Ambient mesh.
+
 ## Issue management
 
 We use GitHub to track all of our bugs and feature requests. Each issue we track has a variety of metadata: