remove black from readme

Author: dulmandakh

README.md

@@ -8,7 +8,7 @@ Export Django monitoring metrics for Prometheus.io
 [![Build Status](https://github.com/korfuri/django-prometheus/actions/workflows/ci.yml/badge.svg)](https://github.com/korfuri/django-prometheus/actions/workflows/ci.yml)
 [![Coverage Status](https://coveralls.io/repos/github/korfuri/django-prometheus/badge.svg?branch=master)](https://coveralls.io/github/korfuri/django-prometheus?branch=master)
 [![PyPi page link -- Python versions](https://img.shields.io/pypi/pyversions/django-prometheus.svg)](https://pypi.python.org/pypi/django-prometheus)
-[![Code style: black](https://img.shields.io/badge/code%20style-black-000000.svg)](https://github.com/psf/black)
+
 
 ## Features