Add support for server_name extension

Section 9.2 of the specification defines server_name
extension as mandatory if not specified otherwise by
an application profile. Thus add its support to the
MVP scope.

Signed-off-by: Ronald Cron <ronald.cron@arm.com>
diff --git a/docs/architecture/tls13-experimental.md b/docs/architecture/tls13-experimental.md
index 9f6d0e4..29cda88 100644
--- a/docs/architecture/tls13-experimental.md
+++ b/docs/architecture/tls13-experimental.md
@@ -87,7 +87,7 @@
 
   | Extension                    |   MVP   | Prototype (1) |
   | ---------------------------- | ------- | ------------- |
-  | server_name                  | no      | YES           |
+  | server_name                  | YES     | YES           |
   | max_fragment_length          | no      | YES           |
   | status_request               | no      | no            |
   | supported_groups             | YES     | YES           |