Gardening: Polish obsolescence message in readme

Change-Id: I1f38f02d776f589b8f6768f96c89a00405a39783
Reviewed-on: https://review.couchbase.org/c/couchbase-java-client/+/205509
Reviewed-by: Michael Reiche <michael.reiche@couchbase.com>
Tested-by: David Nault <david.nault@couchbase.com>

Author: dnault

README.md

@@ -1,6 +1,7 @@
-# Official Couchbase Java SDK
+# (OBSOLETE) Official Couchbase Java SDK
 
-**NOTE: This repository contains the 2.x SDK series, which is currently in maintenance mode. We recommend that you check out our 3.x series, which can be found here: https://github.com/couchbase/couchbase-jvm-clients**
+**NOTE: This repository contains the 2.x SDK series, which reached End of Life in March 2022.
+We recommend that you check out our 3.x series, which can be found here: https://github.com/couchbase/couchbase-jvm-clients**
 
 This project is the official driver for Couchbase when working with Java (or on the JVM). It provides management, CRUD and query facilities through both asynchronous and synchronous APIs.