Remove retired Go Report card badge (#586)

Signed-off-by: Daniel Gonzalez Nothnagel <daniel.gonzalez.nothnagel@sap.com>

Author: gonzolino

README.md

@@ -1,7 +1,6 @@
 # cloud-provider-ironcore
 
 [![REUSE status](https://api.reuse.software/badge/github.com/ironcore-dev/cloud-provider-ironcore)](https://api.reuse.software/info/github.com/ironcore-dev/cloud-provider-ironcore)
-[![Go Report Card](https://goreportcard.com/badge/github.com/ironcore-dev/cloud-provider-ironcore)](https://goreportcard.com/report/github.com/ironcore-dev/cloud-provider-ironcore)
 [![GitHub License](https://img.shields.io/static/v1?label=License&message=Apache-2.0&color=blue)](LICENSE)
 [![PRs Welcome](https://img.shields.io/badge/PRs-welcome-brightgreen.svg)](https://makeapullrequest.com)