Update cookies README

Change-Id: I14b2d32f0f9508c96951a4518c9f255b8b59daff
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6974342
Reviewed-by: Amarjot Gill <[email protected]>
Commit-Queue: Mike Taylor <[email protected]>
Cr-Commit-Position: refs/heads/main@{#1519392}

Author: miketaylr

cookies/README.md

@@ -1,2 +1,7 @@
-This directory contains tests for
-[Leave Secure Cookies Alone](https://tools.ietf.org/html/draft-ietf-httpbis-cookie-alone-01).
+This directory contains tests for various efforts related to the
+standardization of cookies, in different states of maturity:
+
+* [Cookies: HTTP State Management Mechanism](https://datatracker.ietf.org/doc/draft-ietf-httpbis-rfc6265bis/)
+* [Cookies Having Independent Partitioned State](https://www.ietf.org/archive/id/draft-cutler-httpbis-partitioned-cookies-00.html)
+* [Origin Bound Cookies](https://github.com/sbingler/Origin-Bound-Cookies)
+