Add Zenodo DOI

DOI: 10.5281/zenodo.4560581

Author: penyuan

README.md

@@ -8,6 +8,7 @@
 [![standard-readme compliant](https://img.shields.io/badge/readme%20style-standard-brightgreen.svg?style=flat)](https://github.com/RichardLitt/standard-readme)
 [![REUSE compliance status](https://api.reuse.software/badge/github.com/OPEN-NEXT/wp2.2_dev)](https://api.reuse.software/info/github.com/OPEN-NEXT/wp2.2_dev)
 [![Contributor Covenant](https://img.shields.io/badge/Contributor%20Covenant-v2.0%20adopted-ff69b4.svg)](./CODE_OF_CONDUCT.md)
+[![DOI](https://www.zenodo.org/badge/258479982.svg)](https://www.zenodo.org/badge/latestdoi/258479982)
 [![GitHub license](https://img.shields.io/github/license/OPEN-NEXT/wp2.2_dev.svg?style=flat)](./LICENSE)
 
 *Initial proof-of-concept of open source development status dashboard with data-mining & visualisation components*