Add package URL support to the CycloneDX presenter (#164)

* add package URL support to the CycloneDX presenter

Signed-off-by: Alex Goodman <alex.goodman@anchore.com>

* wrap license tags with licenses

Signed-off-by: Alex Goodman <alex.goodman@anchore.com>

syft/pkg/type.go

@@ -1,5 +1,7 @@
 package pkg
 
+import "github.com/package-url/packageurl-go"
+
 // Type represents a Package Type for or within a language ecosystem (there may be multiple package types within a language ecosystem)
 type Type string
 
@@ -38,3 +40,27 @@ var AllPkgs = []Type{
 	JenkinsPluginPkg,
 	GoModulePkg,
 }
+
+func (t Type) PackageURLType() string {
+	switch t {
+	case ApkPkg:
+		return "alpine"
+	case BundlerPkg:
+		return packageurl.TypeGem
+	case DebPkg:
+		return "deb"
+	case EggPkg, WheelPkg, PythonRequirementsPkg, PythonSetupPkg:
+		return packageurl.TypePyPi
+	case NpmPkg, YarnPkg:
+		return packageurl.TypeNPM
+	case JavaPkg, JenkinsPluginPkg:
+		return packageurl.TypeMaven
+	case RpmPkg:
+		return packageurl.TypeRPM
+	case GoModulePkg:
+		return packageurl.TypeGolang
+	default:
+		// TODO: should this be a "generic" purl type instead?
+		return ""
+	}
+}