[MASSEMBLY-991] - Add links to XSDs for 2.2.0

Add links to the assembly-2.2.0.xsd and assembly-component-2.2.0.xsd.
Also fix example in using-container-descriptor-handlers.apt.vm to use mdoVersion.

Author: rmgrimm

src/site/apt/examples/single/using-container-descriptor-handlers.apt.vm

@@ -309,8 +309,8 @@ public class MyCustomDescriptorHandler implements ContainerDescriptorHandler {
   <<<test.properties>>>. With the following descriptor format
 
 +-----
-<assembly xmlns="http://maven.apache.org/ASSEMBLY/2.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-  xsi:schemaLocation="http://maven.apache.org/ASSEMBLY/2.0.0 http://maven.apache.org/xsd/assembly-2.0.0.xsd">
+<assembly xmlns="http://maven.apache.org/ASSEMBLY/${mdoVersion}" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+  xsi:schemaLocation="http://maven.apache.org/ASSEMBLY/${mdoVersion} http://maven.apache.org/xsd/assembly-${mdoVersion}.xsd">
   <id>dist</id>
   <formats>
     <format>zip</format>

src/site/apt/index.apt.vm

@@ -115,6 +115,9 @@ ${project.name}
 
 * Assembly and Component Descriptor Schemas (XSD)
 
+  * {{{/xsd/assembly-2.2.0.xsd}https://maven.apache.org/xsd/assembly-2.2.0.xsd}},
+    {{{/xsd/assembly-component-2.2.0.xsd}https://maven.apache.org/xsd/assembly-component-2.2.0.xsd}} (for version 3.6.0 and higher)
+
   * {{{/xsd/assembly-2.1.1.xsd}https://maven.apache.org/xsd/assembly-2.1.1.xsd}},
     {{{/xsd/assembly-component-2.1.1.xsd}https://maven.apache.org/xsd/assembly-component-2.1.1.xsd}} (for version 3.4.0 and higher)