feat(PackageURL):add package URL for library scan result (#1862)

* add: package url in model.Library

* feat(trivy-to-vuls): add purl for library scan result

* feat(scanner/library): add purl for lockfile scan result

* fix: model.Library test

* fix: trivy-to-vuls test data

* fix: panic case to generate purl

* fix: add blank line

* fix: trivy-to-vuls for using Trivy version 0.49.0 or earlier

* fix: remove comment

* fix: remove print

* fix: testcase for Package.Identifier does not exist version

* fix: add blank line

* fix: expected libs

* fix: PackageURL -> PURL

* fix: blank line

contrib/trivy/pkg/converter.go

@@ -149,6 +149,7 @@ func Convert(results types.Results) (result *models.ScanResult, err error) {
 				libScanner.Libs = append(libScanner.Libs, models.Library{
 					Name:     p.Name,
 					Version:  p.Version,
+					PURL:     getPURL(p),
 					FilePath: p.FilePath,
 				})
 			}
@@ -214,3 +215,10 @@ func isTrivySupportedOS(family ftypes.TargetType) bool {
 	_, ok := supportedFamilies[family]
 	return ok
 }
+
+func getPURL(p ftypes.Package) string {
+	if p.Identifier.PURL == nil {
+		return ""
+	}
+	return p.Identifier.PURL.String()
+}