#2268: remove gcc-8 badge from README

Author: cz4rs

README.md

@@ -4,7 +4,6 @@
 [![codecov](https://codecov.io/gh/DARMA-tasking/vt/branch/develop/graph/badge.svg)](https://codecov.io/gh/DARMA-tasking/vt)
 [![License](https://img.shields.io/badge/License-BSD%203--Clause-orange.svg)](https://opensource.org/licenses/BSD-3-Clause)
 ![](https://github.com/DARMA-tasking/vt/workflows/Docker%20Image%20CI/badge.svg)
-[![gcc-8, ubuntu, mpich, address sanitizer](https://dev.azure.com/DARMA-tasking/DARMA/_apis/build/status/PR%20tests%20(gcc-8%2C%20ubuntu%2C%20mpich%2C%20address%20sanitizer)?branchName=develop&Label=(gcc-8%2C%20ubuntu%2C%20mpich%2C%20address%20sanitizer))](https://dev.azure.com/DARMA-tasking/DARMA/_build/latest?definitionId=9&branchName=develop)
 [![gcc-9, ubuntu, mpich, zoltan](https://dev.azure.com/DARMA-tasking/DARMA/_apis/build/status/PR%20tests%20(gcc-9%2C%20ubuntu%2C%20mpich%2C%20zoltan)?branchName=develop&Label=(gcc-9%2C%20ubuntu%2C%20mpich%2C%20zoltan))](https://dev.azure.com/DARMA-tasking/DARMA/_build/latest?definitionId=10&branchName=develop)
 [![gcc-10, ubuntu, openmpi, no LB](https://dev.azure.com/DARMA-tasking/DARMA/_apis/build/status/PR%20tests%20(gcc-10%2C%20ubuntu%2C%20openmpi%2C%20no%20LB)?branchName=develop&Label=(gcc-10%2C%20ubuntu%2C%20openmpi%2C%20no%20LB))](https://dev.azure.com/DARMA-tasking/DARMA/_build/latest?definitionId=4&branchName=develop)
 [![gcc-11, ubuntu, mpich](https://dev.azure.com/DARMA-tasking/DARMA/_apis/build/status/PR%20tests%20(gcc-11%2C%20ubuntu%2C%20mpich)?branchName=develop&Label=(gcc-11%2C%20ubuntu%2C%20mpich%2C%20trace%20runtime%2C%20coverage))](https://dev.azure.com/DARMA-tasking/DARMA/_build/latest?definitionId=29&branchName=develop)