Update README.md

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Author: chsou

README.md

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+![GitHub](https://img.shields.io/github/license/SoftwareAG/cumulocity-python-api)
+![GitHub release (latest by date)](https://img.shields.io/github/v/release/SoftwareAG/cumulocity-python-api)
+![GitHub Release Date](https://img.shields.io/github/release-date/SoftwareAG/cumulocity-python-api)
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 # cumulocity-python-api
 
 This project is a Python client for the Cumulocity REST API to make it easier to develop programs, scripts, device agents or microservices in Python.