fix(core): XSD version is invalid in the templates (#83)

- Using latest XSD version

spring-configuration-property-documenter-core/src/main/resources/templates/aggregated/xml/header.xml.hbs

@@ -1,6 +1,6 @@
 <configurationProperties  xmlns="https://github.com/rodnansol/spring-configuration-property-documenter"
                           xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-                          xsi:schemaLocation="https://github.com/rodnansol/spring-configuration-property-documenter https://raw.githubusercontent.com/rodnansol/spring-configuration-property-documenter/master/public/schema-0.5.1.xsd">
+                          xsi:schemaLocation="https://github.com/rodnansol/spring-configuration-property-documenter https://raw.githubusercontent.com/rodnansol/spring-configuration-property-documenter/master/public/schema-0.5.0.xsd">
     {{#templateCustomization}}{{#if headerEnabled}}<mainName>{{mainName}}</mainName>
     <mainDescription>{{mainDescription}}</mainDescription>{{/if}}{{#if tableOfContentsEnabled}}
     <tableOfContents>