updated readme to include toJson methods

Author: matthewnitschke

README.md

@@ -17,4 +17,41 @@ void main() {
 }
 ```
 
-You can find more about the `PubspecLock` object in the documentation [here](https://pub.dev/documentation/pubspec_lock_parse/latest/)
+You can find more about the `PubspecLock` object in the documentation [here](https://pub.dev/documentation/pubspec_lock_parse/latest/)
+
+### toJson() methods
+
+`pubspec_lock_parse` includes `.toJson()` methods on each object to allow for easy re-generation/mutation of pubspec files
+
+This can be combined with [yaml_writer](https://github.com/gmpassos/yaml_writer) to re-generate yaml output
+
+```dart
+void main() {
+    final pubspec = PubspecLock(
+        packages: {
+            'somePackage': Package(
+                dependency: 'transitive',
+                description: PathPackageDescription(
+                    path: '../somePackage',
+                    relative: true,
+                )
+            )
+        },
+        sdks: {
+            'dart': VersionConstraint.parse(">=2.17.0 <3.0.0"),
+        }
+    );
+
+    final jsonPubspec = pubspec.toJson(); // outputs Map<String, dynamic>
+    final yamlPubspec = YamlWriter().write(jsonPubspec); // outputs String
+}
+```
+
+`toJson` can also be run on any individual object
+```dart
+// outputs: { path: '../somePackage', relative: true }
+print(PathPackageDescription(
+    path: '../somePackage',
+    relative: true,
+));
+```