docs: update calendar, add news and link release notes to 17.3.9

Signed-off-by: Juan A. Suarez Romero <jasuarez@igalia.com>

docs/index.html

@@ -16,6 +16,16 @@
 
 <h1>News</h1>
 
+<h2>April 18, 2018</h2>
+<p>
+<a href="relnotes/17.3.9.html">Mesa 17.3.9</a> is released.
+This is a bug-fix release.
+<br>
+NOTE: It is anticipated that 17.3.9 will be the final release in the
+17.3 series. Users of 17.3 are encouraged to migrate to the 18.0
+series in order to obtain future fixes.
+</p>
+
 <h2>April 03, 2018</h2>
 <p>
 <a href="relnotes/17.3.8.html">Mesa 17.3.8</a> is released.

docs/release-calendar.html

@@ -37,14 +37,6 @@ if you'd like to nominate a patch in the next stable release.
 <th>Release</th>
 <th>Release manager</th>
 <th>Notes</th>
-</tr>
-<tr>
-<td rowspan="1">17.3</td>
-<td>2018-04-06</td>
-<td>17.3.9</td>
-<td>Juan A. Suarez Romero</td>
-<td>Last planned 17.3.x release</td>
-</tr>
 <tr>
 <td rowspan="4">18.0</td>
 <td>2018-04-06</td>

docs/relnotes.html

@@ -21,6 +21,7 @@ The release notes summarize what's new or changed in each Mesa release.
 </p>
 
 <ul>
+<li><a href="relnotes/17.3.9.html">17.3.9 release notes</a>
 <li><a href="relnotes/17.3.8.html">17.3.8 release notes</a>
 <li><a href="relnotes/18.0.0.html">18.0.0 release notes</a>
 <li><a href="relnotes/17.3.7.html">17.3.7 release notes</a>