Fix for errors+failures parsing package.json

closes: #230

Signed-off-by: Toure Dunnon <toure.dunnon@anchore.com>

syft/pkg/metadata.go

@@ -1,11 +0,0 @@
-package pkg
-
-type MetadataType string
-
-const (
-	UnknownMetadataType MetadataType = "UnknownMetadata"
-	ApkMetadataType     MetadataType = "apk-metadata"
-	DpkgMetadataType    MetadataType = "dpkg-metadata"
-	GemgMetadataType    MetadataType = "gem-metadata"
-	RpmdbMetadataType   MetadataType = "rpmdb-metadata"
-)

syft/pkg/npm_metadata.go

@@ -9,4 +9,5 @@ type NpmMetadata struct {
 	License     string   `mapstructure:"license" json:"license"`
 	Homepage    string   `mapstructure:"homepage" json:"homepage"`
 	Description string   `mapstructure:"description" json:"description"`
+	URL         string   `mapstructure:"url" json:"url"`
 }