readme: added badges

README.md

@@ -1,5 +1,11 @@
 # SwitchBot MQTT client
 
+[![Code style: black](https://img.shields.io/badge/code%20style-black-000000.svg)](https://github.com/psf/black)
+[![CI Pipeline Status](https://github.com/fphammerle/switchbot-mqtt/workflows/tests/badge.svg)](https://github.com/fphammerle/switchbot-mqtt/actions)
+[![Coverage Status](https://coveralls.io/repos/github/fphammerle/switchbot-mqtt/badge.svg?branch=master)](https://coveralls.io/github/fphammerle/switchbot-mqtt?branch=master)
+[![Last Release](https://img.shields.io/pypi/v/switchbot-mqtt.svg)](https://pypi.org/project/switchbot-mqtt/#history)
+[![Compatible Python Versions](https://img.shields.io/pypi/pyversions/switchbot-mqtt.svg)](https://pypi.org/project/switchbot-mqtt/)
+
 MQTT client controlling [SwitchBot button automators](https://www.switch-bot.com/bot)
 
 Compatible with [Home Assistant](https://www.home-assistant.io/)'s