doc: Updating badges (deleting obsolete, adding pypi download count)

Author: QuentinCG

README.md

@@ -1,5 +1,5 @@
 # GSM TC35 Python library
-[![PyPI version](https://badge.fury.io/py/GSMTC35.svg)](https://badge.fury.io/py/GSMTC35) [![Build Status](https://travis-ci.org/QuentinCG/GSM-TC35-Python-Library.svg?branch=master)](https://travis-ci.org/QuentinCG/GSM-TC35-Python-Library) [![codecov](https://codecov.io/gh/QuentinCG/GSM-TC35-Python-Library/branch/master/graph/badge.svg)](https://codecov.io/gh/QuentinCG/GSM-TC35-Python-Library) [![Codacy Badge](https://api.codacy.com/project/badge/Grade/7a2104d9938a493a8d1d4896e2bb0fe2)](https://www.codacy.com/manual/QuentinCG/GSM-TC35-Python-Library?utm_source=github.com&utm_medium=referral&utm_content=QuentinCG/GSM-TC35-Python-Library&utm_campaign=Badge_Grade) [![License: MIT](https://img.shields.io/badge/License-MIT-brightgreen.svg)](https://github.com/QuentinCG/GSM-TC35-Python-Library/blob/master/LICENSE.md) [![Donate](https://img.shields.io/badge/Donate-PayPal-blue.svg)](https://paypal.me/QuentinCG)
+[![PyPI version](https://badge.fury.io/py/GSMTC35.svg)](https://badge.fury.io/py/GSMTC35) [![codecov](https://codecov.io/gh/QuentinCG/GSM-TC35-Python-Library/branch/master/graph/badge.svg)](https://codecov.io/gh/QuentinCG/GSM-TC35-Python-Library) [![License: MIT](https://img.shields.io/badge/License-MIT-brightgreen.svg)](https://github.com/QuentinCG/GSM-TC35-Python-Library/blob/master/LICENSE.md) [![Donate](https://img.shields.io/badge/Donate-PayPal-blue.svg)](https://paypal.me/QuentinCG) [![Downloads](https://static.pepy.tech/badge/GSMTC35)](https://pepy.tech/project/GSMTC35) [![Downloads](https://static.pepy.tech/badge/GSMTC35/month)](https://pepy.tech/project/GSMTC35)
 
 ## What is it