[doc] Mark Bionic and Buster as unsupported for Y

We have dropped both Ubuntu 18.04 and Debian 10 support for Yoga.
That should be reflected in compatability matrix as well.

Change-Id: Ie77e7c46b8fe1ca384b4e56d75ce551867647cb7

doc/source/admin/upgrades/os-compatibility-matrix.html

@@ -283,14 +283,14 @@
         <th rowspan="2" style="vertical-align: middle">Yoga</td>
         <td>source</td>
         <td>✘</td>
-        <td>✔</td>
+        <td>✘</td>
         <td>✔</td>
         <td class="warning">E</td>
         <td>✘</td>
-        <td>✔</td>
-        <td>✔</td>
         <td>✘</td>
         <td>✔</td>
+        <td>✘</td>
+        <td>✘</td>
         <td>✔</td>
         <td>✔</td>
     </tr>