mark the library as abandoned (#134)

Co-authored-by: oleksandr.dombrovskyi <oleksandr.dombrovskyi@real-digital.de>

Author: odombrovskyi-dev

README.md

@@ -4,6 +4,9 @@
 [![Coverage Status](https://coveralls.io/repos/github/hitmeister/api-sdk-php/badge.svg?branch=master)](https://coveralls.io/github/hitmeister/api-sdk-php?branch=master)
 [![Total Downloads](http://img.shields.io/packagist/dt/hitmeister/api-sdk.svg)](https://packagist.org/packages/hitmeister/api-sdk)
 
+> **The v1 API doesn't exist anymore, and this package is abandoned and no longer maintained.** No new versions will be released.
+> The API version 2 is available at [this url](https://sellerapi.kaufland.com/).
+
 PHP client for [Kaufland.de Onlineshop API](https://www.kaufland.de/api/v1/).
 
 ## Install

composer.json

@@ -9,6 +9,7 @@
         }
     ],
     "license": "MIT",
+    "abandoned": true,
     "minimum-stability": "stable",
     "keywords": [
         "hitmeister",