Add badges to README

Author: jluethi

README.md

@@ -1,5 +1,10 @@
 # fractal-helper-tasks
 
+[![License](https://img.shields.io/badge/License-BSD_3--Clause-blue.svg)](LICENSE)
+![Python version](https://img.shields.io/badge/python-%3E%3D3.9-blue)
+![GitHub Workflow Status](https://img.shields.io/github/actions/workflow/status/jluethi/fractal-helper-tasks/your-workflow-file.yml?branch=main)
+[![codecov](https://codecov.io/gh/jluethi/fractal-helper-tasks/graph/badge.svg?token=ednmg2GzOw)](https://codecov.io/gh/jluethi/fractal-helper-tasks)
+
 Collection of Fractal helper tasks
 
 ## Development instructions