Support for concludedValue in evidence/identity

[goldmann]

This adds missing support for serialization and deserialization of data that uses the evidence.identity[].concludedValue field which was introduced in CycloneDX 1.6.

https://cyclonedx.org/docs/1.6/json/#components_items_evidence_identity_oneOf_i0_items_concludedValue

[nscuro]

Please also update convert.go to strip this field when converting to spec versions < 1.6:

cyclonedx-go/convert.go

Lines 204 to 222 in 3ed34da

	if specVersion < SpecVersion1_6 {
	// Spec version 1.5 uses only one Identity.
	// cf. https://cyclonedx.org/docs/1.5/json/#components_items_evidence_identity
	if c.Evidence.Identity != nil {
	ids := *c.Evidence.Identity
	ids = ids[:1]
	c.Evidence.Identity = &ids
	}
	if c.Evidence.Occurrences != nil {
	for i := range *c.Evidence.Occurrences {
	occ := &(*c.Evidence.Occurrences)[i]
	occ.Line = nil
	occ.Offset = nil
	occ.Symbol = ""
	occ.AdditionalContext = ""
	}
	}
	}