Fixed MIT badge (#23)

* Fixed MIT badge

README.md

@@ -3,7 +3,7 @@
 # Corbado Go SDK
 
 [![Go Reference](https://pkg.go.dev/badge/github.com/corbado/corbado-go.svg)](https://pkg.go.dev/github.com/corbado/corbado-go)
-[![License](https://poser.pugx.org/corbado/php-sdk/license.svg)](https://packagist.org/packages/corbado/php-sdk)
+[![License: MIT](https://img.shields.io/badge/License-MIT-yellow.svg)](https://opensource.org/licenses/MIT)
 [![Test Status](https://github.com/corbado/corbado-go/workflows/tests/badge.svg)](https://github.com/corbado/corbado-go/actions?query=workflow%3Atests)
 [![Go Report Card](https://goreportcard.com/badge/github.com/corbado/corbado-go)](https://goreportcard.com/report/github.com/corbado/corbado-go)
 [![documentation](https://img.shields.io/badge/documentation-Corbado_Backend_API_Reference-blue.svg)](https://api.corbado.com/docs/api/)