schema: Add microcode element to capability grammar

https://bugzilla.redhat.com/show_bug.cgi?id=1572491

Commit id 'd2440f3b' added printing the <microcode> for the
capabilities, but didn't update the capabilities schema.

While at it, update capabilityschemadata for caps-test2
and caps-test3 to output some value for validation.
Signed-off-by: NJohn Ferlan <jferlan@redhat.com>
ACKed-by Michal Privoznik <mprivozn@redhat.com>

docs/schemas/capability.rng

@@ -102,6 +102,13 @@
         <text/>
       </element>
     </optional>
+    <optional>
+      <element name='microcode'>
+        <attribute name='version'>
+          <ref name='positiveInteger'/>
+        </attribute>
+      </element>
+    </optional>
     <element name='topology'>
       <attribute name='sockets'>
         <ref name='positiveInteger'/>

tests/capabilityschemadata/caps-test2.xml

@@ -5,6 +5,7 @@
       <arch>x86_64</arch>
       <model>SandyBridge</model>
       <vendor>Intel</vendor>
+      <microcode version='36'/>
       <topology sockets='1' cores='2' threads='2'/>
       <feature name='osxsave'/>
       <feature name='pdcm'/>

tests/capabilityschemadata/caps-test3.xml

@@ -6,6 +6,7 @@
       <arch>x86_64</arch>
       <model>Westmere</model>
       <vendor>Intel</vendor>
+      <microcode version='36'/>
       <topology sockets='1' cores='6' threads='2'/>
       <feature name='rdtscp'/>
       <feature name='pdpe1gb'/>