Update README.md

Author: jkleinj

README.md

@@ -3,7 +3,7 @@
 [![release](https://img.shields.io/badge/release-v3.4-green?logo=docker)](https://hub.docker.com/repository/docker/jkleinj150999/popscomp/)
 [![wiki](https://img.shields.io/badge/wiki-orange)](https://github.com/Fraternalilab/POPScomp/wiki)
 [![License](https://img.shields.io/badge/license-GPL-blue.svg)](http://www.gnu.org/licenses/gpl-3.0.en.html)
-[![DOI][![DOI](https://zenodo.org/badge/182454886.svg)](https://doi.org/10.5281/zenodo.3679109)
+[![DOI](https://zenodo.org/badge/182454886.svg)](https://doi.org/10.5281/zenodo.3679109)
 [![C CI](https://github.com/Fraternalilab/POPScomp/workflows/C%20CI/badge.svg)](https://github.com/Fraternalilab/POPScomp/blob/main/.github/workflows/ccpp.yml)
 [![R CI](https://github.com/Fraternalilab/POPScomp/workflows/R%20CI/badge.svg)](https://github.com/Fraternalilab/POPScomp/blob/main/.github/workflows/main.yml)