docs: update README.md

README.md

@@ -4,7 +4,7 @@ A simple yet fast header-only library to read/write, serialize/deserialize STL (
 [![Commitizen friendly](https://img.shields.io/badge/commitizen-friendly-brightgreen.svg?style=flat-square)](http://commitizen.github.io/cz-cli/)
 [![Conventional Commits](https://img.shields.io/badge/Conventional%20Commits-1.0.0-yellow.svg?style=flat-square)](https://conventionalcommits.org)
 [![PyPI license](https://img.shields.io/pypi/l/ansicolortags.svg?style=flat-square)](LICENSE)  
-[![pypi](https://badge.fury.io/py/openstl.png?style=flat-square)](https://badge.fury.io/py/openstl)
+[![pypi](https://badge.fury.io/py/openstl.svg?style=flat-square)](https://badge.fury.io/py/openstl)
 [![build](https://github.com/Innoptech/OpenSTL/actions/workflows/publish-to-test-pypi.yml/badge.svg?style=flat-square)](https://github.com/Innoptech/OpenSTL/actions/workflows/publish-to-test-pypi.yml)
 [![Python](https://img.shields.io/pypi/pyversions/openstl.svg)](https://pypi.org/project/openstl/)