docs: update release calendar for 18.1 series

v2: extend 18.1 series (Andres)
v3: fix copy/paste typo (Engestrom)

CC: Andres Gomez <agomez@igalia.com>
CC: Emil Velikov <emil.l.velikov@gmail.com>
CC: Dylan Baker <dylan@pnwbakers.com>
Reviewed-by: Andres Gomez <agomez@igalia.com>
Reviewed-by: Dylan Baker <dylan@pnwbakers.com>

docs/release-calendar.html

@@ -46,53 +46,46 @@ if you'd like to nominate a patch in the next stable release.
 <td>Last planned 18.0.x release</td>
 </tr>
 <tr>
-<td rowspan="8">18.1</td>
-<td>2018-04-20</td>
-<td>18.1.0rc1</td>
-<td>Dylan Baker</td>
+<td rowspan="7">18.1</td>
+<td>2018-06-01</td>
+<td>18.1.1</td>
+<td>Emil Velikov</td>
 <td></td>
 </tr>
 <tr>
-<td>2018-04-27</td>
-<td>18.1.0rc2</td>
-<td>Dylan Baker</td>
+<td>2018-06-15</td>
+<td>18.1.2</td>
+<td>Emil Velikov</td>
 <td></td>
 </tr>
 <tr>
-<td>2018-05-04</td>
-<td>18.1.0rc3</td>
-<td>Dylan Baker</td>
+<td>2018-06-29</td>
+<td>18.1.3</td>
+<td>Emil Velikov</td>
 <td></td>
 </tr>
 <tr>
-<td>2018-05-11</td>
-<td>18.1.0rc4</td>
-<td>Dylan Baker</td>
-<td>Last planned RC/Final release</td>
-</tr>
-<tr>
-<td>TBD</td>
-<td>18.1.1</td>
+<td>2018-07-13</td>
+<td>18.1.4</td>
 <td>Emil Velikov</td>
 <td></td>
 </tr>
 <tr>
-<td>TBD</td>
-<td>18.1.2</td>
+<td>2018-07-27</td>
+<td>18.1.5</td>
 <td>Emil Velikov</td>
 <td></td>
 </tr>
 <tr>
-<td>TBD</td>
-<td>18.1.3</td>
+<td>2018-08-10</td>
+<td>18.1.6</td>
 <td>Emil Velikov</td>
 <td></td>
 </tr>
-<tr>
-<td>TBD</td>
-<td>18.1.4</td>
+<td>2018-08-24</td>
+<td>18.1.7</td>
 <td>Emil Velikov</td>
-<td>Last planned RC/Final release</td>
+<td>Last planned 18.1.x release</td>
 </tr>
 <tr>
 <td rowspan="4">18.2</td>