docs: update readme and add sonar and npm badges

README.md

@@ -1,12 +1,16 @@
 # PayOne Node SDK
 
+[![Quality Gate Status](https://sonarcloud.io/api/project_badges/measure?project=PAYONE-GmbH_PCP-server-nodeJS-SDK&metric=alert_status)](https://sonarcloud.io/summary/new_code?id=PAYONE-GmbH_PCP-server-nodeJS-SDK)
+[![Coverage](https://sonarcloud.io/api/project_badges/measure?project=PAYONE-GmbH_PCP-server-nodeJS-SDK&metric=coverage)](https://sonarcloud.io/summary/new_code?id=PAYONE-GmbH_PCP-server-nodeJS-SDK)
+[![npm](https://img.shields.io/npm/v/pcp-server-nodejs-sdk)](https://www.npmjs.com/package/pcp-server-nodejs-sdk)
+[![npm downloads](https://img.shields.io/npm/dw/pcp-server-nodejs-sdk)](https://www.npmjs.com/package/pcp-server-nodejs-sdk)
+
+**NOTE:** This SDK is still under development. Some things may be broken, features may change in non-compatible ways or will be removed completely.
+
 Welcome to the Node SDK for the PayOne PCP platform! This repository contains a powerful, easy-to-use software development kit (SDK) designed to simplify the integration of online payment processing into your applications.
 
 ### TODOS
 
-- [ ] Setup changelog
-- [ ] Setup sonarcloud
-- [ ] Setup Github actions
 - [ ] Write more tests
 
 ## Table of Contents