Release: add release note link to SUPPORT.md

In order to have a link to the release notes in the feature list
generated from SUPPORT.md add that link in the "Release Support"
section of that file.

The real link needs to be adapted when the version is being released.

Signed-off-by: Juergen Gross <jgross@suse.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>

SUPPORT.md

@@ -13,6 +13,7 @@ for the definitions of the support status levels etc.
     Initial-Release: 2017-12-13
     Supported-Until: 2019-06-13
     Security-Support-Until: 2020-12-13
+    Release-Notes: <a href="https://wiki.xenproject.org/wiki/Xen_Project_4.10_Release_Notes">RN</a>
 
 # Feature Support