Update the 11.3-RELEASE schedule to reflect RC1 builds have started.

Add the new releng/11.3 branch to the releng index page.
Add new __FreeBSD_versions for 11.3 to the Porter's Handbook.

Approved by:	re (implicit)
Sponsored by:	The FreeBSD Foundation

en_US.ISO8859-1/books/porters-handbook/versions/chapter.xml

@@ -2646,6 +2646,21 @@ is spelled &amp;, < is &lt; and > is &gt;.
 	      libunwind, lld, lldb and openmp 8.0.0 final release
 	      r356365.</entry>
 	  </row>
+
+	  <row>
+	    <entry>1103000</entry>
+	    <entry><revnumber>r349026</revnumber></entry>
+	    <entry>June 14, 2019</entry>
+	    <entry><literal>releng/11.3</literal> branched
+	      from <literal>stable/11</literal>.</entry>
+	  </row>
+
+	  <row>
+	    <entry>1103500</entry>
+	    <entry><revnumber>r349027</revnumber></entry>
+	    <entry>June 14, 2019</entry>
+	    <entry>11-STABLE after releng/11.3 branched.</entry>
+	  </row>
 	</tbody>
       </tgroup>
     </table>

en_US.ISO8859-1/htdocs/releases/11.3R/schedule.xml

@@ -106,7 +106,7 @@
       <tr>
 	<td>&local.branch.releng; branch</td>
 	<td>14&nbsp;June&nbsp;2019</td>
-	<td>-</td>
+	<td>14&nbsp;June&nbsp;2019</td>
 	<td>Subversion branch created; future release engineering
 	  proceeds on this branch.</td>
       </tr>
@@ -114,7 +114,7 @@
       <tr>
 	<td>RC1 builds begin</td>
 	<td>14&nbsp;June&nbsp;2019</td>
-	<td>-</td>
+	<td>14&nbsp;June&nbsp;2019</td>
 	<td>First release candidate.</td>
       </tr>
 

en_US.ISO8859-1/htdocs/releng/index.xml

@@ -118,6 +118,13 @@
       <td>Development branch for FreeBSD 11-STABLE.</td>
     </tr>
 
+    <tr>
+      <td><tt>releng/11.3</tt></td>
+      <td>Frozen</td>
+      <td>&contact.re;</td>
+      <td>FreeBSD 11.3 supported errata fix branch.</td>
+    </tr>
+
     <tr>
       <td><tt>releng/11.2</tt></td>
       <td>Frozen</td>