readme: Add badge for release and issues

Signed-off-by: Ajay Bhargav <[email protected]>

Author: ajaybhargav

README.md

@@ -3,3 +3,5 @@
 Software development kit for SIWI GSM modules
 
 [![Documentation Status](https://readthedocs.org/projects/siwisdk/badge/?version=latest)](https://siwisdk.readthedocs.io/en/latest/?badge=latest)
+[![Github Issues](https://img.shields.io/github/issues/siwiembedded/siwisdk.svg)](http://github.com/siwiembedded/siwisdk/issues)
+[![Github Releases](https://img.shields.io/github/release/siwiembedded/siwisdk.svg)](https://github.com/siwiembedded/siwisdk/releases)