Added remaining root objects.

Signed-off-by: Steve Springett <steve@springett.us>

Author: stevespringett

schema/2.0/cyclonedx-2.0.schema.json

@@ -78,6 +78,15 @@
     },
     "citations": {
       "$ref": "model/cyclonedx-citation-2.0.schema.json#/$defs/citations"
+    },
+    "properties": {
+      "$ref": "model/cyclonedx-common-2.0.schema.json#/$defs/properties"
+    },
+    "externalReferences": {
+      "$ref": "model/cyclonedx-common-2.0.schema.json#/$defs/externalReferences"
+    },
+    "signature": {
+      "$ref": "model/cyclonedx-common-2.0.schema.json#/$defs/signature"
     }
   }
 }