releases/lts: add dates for no longer maintained entries

It would be useful to show rough "Bugfix until" and "Security patches
until" dates for the no longer maintained LTS versions (similar to how
we do for the currently maintained LTS versions).

Let's make it so!

app/templates/releases/lts.hbs

@@ -83,78 +83,108 @@
       <th>LTS version</th>
       <th>Last minor release</th>
       <th>Last minor release date</th>
+      <th>Bugfixes until</th>
+      <th>Security patches until</th>
     </tr>
   </thead>
   <tbody>
     <tr>
       <td>4.8</td>
       <td>4.8.6</td>
       <td>June 2023</td>
+      <td>August 2023</td>
+      <td>December 2023</td>
     </tr>
     <tr>
       <td>4.4</td>
       <td>4.4.5</td>
       <td>May 2023</td>
+      <td>March 2023</td>
+      <td>July 2023</td>
     </tr>
     <tr>
       <td>3.28</td>
       <td>3.28.12</td>
       <td>May 2023</td>
+      <td>August 2022</td>
+      <td>January 2023</td>
     </tr>
     <tr>
       <td>3.24</td>
       <td>3.24.7</td>
       <td>November 2022</td>
+      <td>November 2021</td>
+      <td>March 2022</td>
     </tr>
     <tr>
       <td>3.20</td>
       <td>3.20.6</td>
       <td>November 2020</td>
+      <td>May 2021</td>
+      <td>September 2021</td>
     </tr>
     <tr>
       <td>3.16</td>
       <td>3.16.10</td>
       <td>August 2020</td>
+      <td>November 2020</td>
+      <td>March 2021</td>
     </tr>
     <tr>
       <td>3.12</td>
       <td>3.12.4</td>
       <td>May 2020</td>
+      <td>June 2020</td>
+      <td>October 2020</td>
     </tr>
     <tr>
       <td>3.8</td>
       <td>3.8.3</td>
       <td>June 2019</td>
+      <td>December 2019</td>
+      <td>April 2020</td>
     </tr>
     <tr>
       <td>3.4</td>
       <td>3.4.8</td>
       <td>January 2019</td>
+      <td>June 2019</td>
+      <td>October 2019</td>
     </tr>
     <tr>
       <td>2.18</td>
       <td>2.18.2</td>
       <td>February 2018</td>
+      <td>October 2018</td>
+      <td>February 2019</td>
     </tr>
     <tr>
       <td>2.16</td>
       <td>2.16.4</td>
       <td>February 2018</td>
+      <td>July 2018</td>
+      <td>December 2018</td>
     </tr>
     <tr>
       <td>2.12</td>
       <td>2.12.2</td>
       <td>April 2017</td>
+      <td>January 2018</td>
+      <td>May 2018</td>
     </tr>
     <tr>
       <td>2.8</td>
       <td>2.8.3</td>
       <td>November 2016</td>
+      <td>June 2017</td>
+      <td>October 2017</td>
     </tr>
     <tr>
       <td>2.4</td>
       <td>2.4.5</td>
       <td>April 2016</td>
+      <td>December 2016</td>
+      <td>April 2017</td>
     </tr>
   </tbody>
-</table>
+</table>