add cpan badge

Author: freyfogle

README.md

@@ -1,5 +1,7 @@
 
-[![Build Status](https://travis-ci.org/OpenCageData/perl-Geo-Coder-OpenCage.svg?branch=master)](https://travis-ci.org/OpenCageData/perl-Geo-Code-OpenCage) [![Kritika Analysis Status](https://kritika.io/users/OpenCage/repos/2893424605329847/heads/master/status.svg)](https://kritika.io/orgs/OpenCage/repos/2893424605329847/heads/master/)
+[![Build Status](https://travis-ci.org/OpenCageData/perl-Geo-Coder-OpenCage.svg?branch=master)](https://travis-ci.org/OpenCageData/perl-Geo-Code-OpenCage) 
+[![Kritika Analysis Status](https://kritika.io/users/OpenCage/repos/2893424605329847/heads/master/status.svg)](https://kritika.io/orgs/OpenCage/repos/2893424605329847/heads/master/)
+[![CPAN](https://img.shields.io/cpan/v/Geo-Coder-OpenCage.svg?style=flat-square)](https://metacpan.org/pod/Geo::Coder::OpenCage)
 
 # Geo::Coder::OpenCage