add a Debian badge

Author: eddelbuettel

ChangeLog

@@ -1,3 +1,7 @@
+2020-01-22  Dirk Eddelbuettel  <edd@debian.org>
+
+	* README.md: README.md: Add a Debian badge
+
 2019-11-16  Dirk Eddelbuettel  <edd@debian.org>
 
 	* DESCRIPTION (Version, Date): Release 0.3.3.7.0

README.md

@@ -4,8 +4,9 @@
 [![License](http://img.shields.io/badge/license-GPL%20%28%3E=%202%29-brightgreen.svg?style=flat)](http://www.gnu.org/licenses/gpl-2.0.html) 
 [![License](http://img.shields.io/badge/license-MPL2-brightgreen.svg?style=flat)](http://www.mozilla.org/MPL/2.0/) 
 [![CRAN](http://www.r-pkg.org/badges/version/RcppEigen)](https://cran.r-project.org/package=RcppEigen) 
-[![Dependencies](https://tinyverse.netlify.com/badge/RcppEigen)](https://cran.r-project.org/package=RcppEigen)  
-[![Downloads](http://cranlogs.r-pkg.org/badges/RcppEigen?color=brightgreen)](http://www.r-pkg.org/pkg/RcppEigen) 
+[![Dependencies](https://tinyverse.netlify.com/badge/RcppEigen)](https://cran.r-project.org/package=RcppEigen)
+[![Debian package](https://img.shields.io/debian/v/r-cran-rcppeigen/sid?color=green)](https://packages.debian.org/sid/r-cran-rcppeigen)  
+[![Downloads](http://cranlogs.r-pkg.org/badges/RcppEigen?color=brightgreen)](http://www.r-pkg.org/pkg/RcppEigen)
 [![CRAN use](https://jangorecki.gitlab.io/rdeps/RcppEigen/CRAN_usage.svg?sanitize=true)](https://cran.r-project.org/package=RcppEigen)
 [![BioConductor use](https://jangorecki.gitlab.io/rdeps/RcppEigen/BioC_usage.svg?sanitize=true)](https://cran.r-project.org/package=RcppEigen)
 [![StackOverflow](https://img.shields.io/badge/stackoverflow-rcpp-orange.svg)](https://stackoverflow.com/questions/tagged/rcpp)