update server incompat to v8.1

Author: rustagir

source/upgrade.txt

@@ -435,13 +435,13 @@ end-of-life (EOL).
 To learn more about the MongoDB support for EOL products,
 see the `Legacy Support Policy <https://www.mongodb.com/support-policy/legacy>`__.
 
-.. _java-server-8.0-incompatibility:
+.. _java-server-8.1-incompatibility:
 
-Server Version 8.0 Support Changes
+Server Version 8.1 Support Changes
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 You cannot use a 3.x version of the {+driver-short+} to connect to a
-deployment running {+mdb-server+} v8.0. Starting in {+mdb-server+} v8.0,
+deployment running {+mdb-server+} v8.1. Starting in {+mdb-server+} v8.1,
 the ``buildinfo`` command requires authentication, causing an
 incompatibility with the v3.x driver.