Add related finding assembly. usnistgov#1120

src/metaschema/oscal_poam_metaschema.xml

@@ -129,6 +129,16 @@
                 </remarks>
             </define-assembly>
 
+            <define-assembly name="related-finding" min-occurs="0" max-occurs="unbounded">
+                <formal-name>Related Finding</formal-name>
+                <description>Relates the poam-item to a set of referenced findings.</description>
+                <group-as name="related-findings" in-json="ARRAY"/>
+                <define-flag name="finding-uuid" as-type="uuid" required="yes">
+                    <formal-name>Observation Universally Unique Identifier Reference</formal-name>
+                    <description>A <a href="/concepts/identifier-use/#machine-oriented">machine-oriented</a> identifier reference to a finding defined in the list of findings.</description>
+                </define-flag>
+            </define-assembly>
+
             <!-- TODO: add link; check in the other assessment models -->
             <!-- CHANGED: removed "collected" and "expires" (moved to observation) by brianrufgsa -->
             <!-- CHANGED: removed "objective-status" per brianrufgsa -->