Add 4.3.1 release date

Signed-off-by: Roger Sheen <[email protected]>

Author: infotexture

release-notes/index.dita

@@ -28,7 +28,7 @@
 
   <reference id="v4.3.1" outputclass="mark">
     <title>DITA-OT <keyword keyref="maintenance-version"/>
-      <!--<ph outputclass="small text-muted">released mmmm D, yyyy</ph>-->
+      <ph outputclass="small text-muted">released March 23, 2025</ph>
     </title>
     <refbody>
       <section>