[site-release] Update plugin version to 2.4.0

webapp/WEB-INF/plugins/forms.xml

 <?xml version="1.0" encoding="UTF-8" standalone="no"?><plug-in>
     <name>forms</name>
     <class>fr.paris.lutece.plugins.forms.service.FormsPlugin</class>
-    <version>2.4.0-SNAPSHOT</version>
+    <version>2.4.0</version>
     <documentation/>
     <installation/>
     <changes/>