Additional schema updates to match existing XML files

Author: gmarcosb

src/app/zap-templates/zcl/zcl.xsd

@@ -451,7 +451,7 @@ This schema describes the format of the XML files, that describe the ZCL specifi
   <xs:element name="event">
     <xs:complexType>
       <xs:choice maxOccurs="unbounded">
-        <xs:element ref="description" minOccurs="1" maxOccurs="1"/>
+        <xs:element ref="description" />
         <xs:element minOccurs="0" maxOccurs="unbounded" name="access" type="access"/>
         <xs:element minOccurs="0" maxOccurs="unbounded" name="field" type="eventField"/>
       </xs:choice>