Add readme

Author: mosuem

README.md

@@ -8,11 +8,13 @@ This repository is home to various Dart packages under the [dart.dev](https://pu
 
 | Package | Description | Version |
 |---|---|---|
+| [args](pkgs/args/) | Library for defining parsers for parsing raw command-line arguments into a set
+  of options and values. | [![pub package](https://img.shields.io/pub/v/args.svg)](https://pub.dev/packages/args) |
 
 ## Publishing automation
 
 For information about our publishing automation and release process, see
 https://github.com/dart-lang/ecosystem/wiki/Publishing-automation.
 
 For additional information about contributing, see our
-[contributing](CONTRIBUTING.md) page.
+[contributing](CONTRIBUTING.md) page.