Update README with link to Packagist installation

Author: timoschinkel

CHANGELOG.md

@@ -4,6 +4,10 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## Unreleased
+### Changed
+- Updated README with link to Packagist 
+
 ## [1.0.0] - 2020-02-25
 Initial set up.
 

README.md

@@ -13,7 +13,9 @@ This might be solved by using a solution similar to the middleware defined in [P
 
 ## Installation
 
-Coming soon.
+```bash
+composer require coolblue/http-client-middleware 
+```
 
 ## Usage 
 Middleware needs to comply to the interface `\Coolblue\Http\Client\MiddlewareInterface`: