add downloads counter

Author: dkobran

README.md

@@ -4,7 +4,7 @@ Gradient CLI
 =================
 
 ![PyPI](https://img.shields.io/pypi/v/gradient)
-[![codecov](https://codecov.io/gh/Paperspace/gradient-cli/branch/master/graph/badge.svg)](https://codecov.io/gh/Paperspace/gradient-cli)
+[![Downloads](https://pepy.tech/badge/gradient)](https://pepy.tech/project/gradient)
 
 <br>