Remove stackoverflow badge

Author: eddelbuettel

README.md

@@ -13,7 +13,6 @@
 [![Downloads (total)](https://cranlogs.r-pkg.org/badges/grand-total/RcppEigen?color=brightgreen)](https://www.r-pkg.org:443/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)
 [![JSS](https://img.shields.io/badge/JSS-10.18637%2Fjss.v052.i05-brightgreen)](https://doi.org/10.18637/jss.v052.i05)