Type in package name

Author: WyriHaximus

README.md

@@ -204,7 +204,7 @@ The recommended way to install this library is [through Composer](https://getcom
 This will install the latest supported version:
 
 ```bash
-$ composer require react/stream-react
+$ composer require react/promise-stream
 ```
 
 See also the [CHANGELOG](CHANGELOG.md) for details about version upgrades.