[+] add downloads badge

Author: pashagolub

README.md

@@ -1,5 +1,6 @@
 [![License: MIT](https://img.shields.io/badge/License-MIT-green.svg)](https://opensource.org/licenses/MIT)
 [![Release](https://img.shields.io/github/release/cybertec-postgresql/patroni-windows-packaging.svg)](https://github.com/cybertec-postgresql/patroni-windows-packaging/releases/latest)
+[![Github All Releases](https://img.shields.io/github/downloads/cybertec-postgresql/patroni-windows-packaging/total?style=flat-square)](https://github.com/cybertec-postgresql/patroni-windows-packaging/releases)
 
 # patroni-windows-packaging
 Automate installing and launching of Patroni under Windows