Add dart support (#919)

Co-authored-by: Alex Goodman <alex.goodman@anchore.com>

internal/formats/common/spdxhelpers/source_info.go

@@ -13,6 +13,8 @@ func SourceInfo(p pkg.Package) string {
 		answer = "acquired package info from RPM DB"
 	case pkg.ApkPkg:
 		answer = "acquired package info from APK DB"
+	case pkg.DartPubPkg:
+		answer = "acquired package info from pubspec manifest"
 	case pkg.DebPkg:
 		answer = "acquired package info from DPKG DB"
 	case pkg.NpmPkg:

internal/formats/common/spdxhelpers/source_info_test.go

@@ -126,6 +126,14 @@ func Test_SourceInfo(t *testing.T) {
 				"from PHP composer manifest",
 			},
 		},
+		{
+			input: pkg.Package{
+				Type: pkg.DartPubPkg,
+			},
+			expected: []string{
+				"from pubspec manifest",
+			},
+		},
 	}
 	var pkgTypes []pkg.Type
 	for _, test := range tests {