Nuget UNLICENSED License Expression Produces Invalid File

[south11235]

Nuget documentation defines UNLICENSED as a valid license-expression: https://github.com/nuget/home/wiki/packaging-license-within-the-nupkg-(technical-spec)#nugets-license-expression-abnf

dotnet-CycloneDX: version: 3.0.6

Steps to reproduce:

1. .nuspec file contains <license type="expression">UNLICENSED</license>
2. create cyclonedx file

Result:
Output contains:

      <licenses>
        <license>
          <id>UNLICENSED</id>
        </license>
      </licenses>

This is invalid because a license ID element is required to contain an SPDX-valid string. "UNLICENSED" is not allowed ( https://cyclonedx.org/docs/1.6/json/#tab-pane_metadata_component_licenses_oneOf_i0_items_license_oneOf_i0 ) on the list of valid SPDX ENUM values.

cyclonedx --version: 0.27.1+6c0e6c8f45d446ed4a28891040592e4ae4a39c3c
cyclonedx validate --input-file target_dotnet.xml --input-format xml --fail-on-errors --input-version=v1_5

Validating XML BOM...
Validation failed at line number 861 and position 27: The 'http://cyclonedx.org/schema/bom/1.5:id' element is invalid - The value 'UNLICENSED' is invalid according to its datatype 'http://cyclonedx.org/schema/spdx:licenseId' - The Enumeration constraint failed.
BOM is not valid.

Desired Output:

Reference via License Name:

      <licenses>
        <license>
          <name>UNLICENSED</name>
        </license>
      </licenses>

[mtsfoni]

Probably, can make a simple condition to handle the specific case <license type="expression">UNLICENSED</license> as name and not id.