feat: licenses acknowledgement SHOULD be unique

schema/2.0/model/cyclonedx-license-2.0.schema.json

@@ -7,7 +7,7 @@
   "$defs": {
     "licenseChoice": {
       "title": "License Choice",
-      "description": "A list of SPDX licenses and/or named licenses and/or SPDX License Expression.",
+      "description": "A list of SPDX licenses and/or named licenses and/or SPDX License Expression.\n\nFor each value of the acknowledgement enumeration, the array should contain at most one item whose acknowledgement property has that value. Items whose acknowledgement property is absent are not subject to this constraint.",
       "type": "array",
       "items": {
         "oneOf": [

schema/2.0/model/cyclonedx-metadata-2.0.schema.json

@@ -54,7 +54,7 @@
         },
         "licenses": {
           "title": "BOM License(s)",
-          "description": "The license information for the BOM document.\nThis may be different from the license(s) of the component(s) that the BOM describes.",
+          "description": "The license information for the BOM document.\nThis may be different from the license(s) of the component(s) that the BOM describes.\n\nFor each value of the acknowledgement enumeration, the array should contain at most one item whose acknowledgement property has that value.\nItems whose acknowledgement property is absent are not subject to this constraint.",
           "$ref": "cyclonedx-license-2.0.schema.json#/$defs/licenseChoice"
         },
         "distributionConstraints": {