README: drop the CentOS CI SELinux job

It has been failing for more than a year and I don't think that anyone
cares about the stuff it keeps finding.

README.md

@@ -10,7 +10,6 @@ System and Service Manager
 [![CentOS CI - CentOS 8](https://jenkins-systemd.apps.ocp.cloud.ci.centos.org/buildStatus/icon?subject=CentOS%20CI%20-%20CentOS%208&job=upstream-centos8)](https://jenkins-systemd.apps.ocp.cloud.ci.centos.org/job/upstream-centos8/)<br/>
 [![CentOS CI - Arch](https://jenkins-systemd.apps.ocp.cloud.ci.centos.org/buildStatus/icon?subject=CentOS%20CI%20-%20Arch&job=upstream-vagrant-archlinux)](https://jenkins-systemd.apps.ocp.cloud.ci.centos.org/job/upstream-vagrant-archlinux/)<br/>
 [![CentOS CI - Arch (sanitizers)](https://jenkins-systemd.apps.ocp.cloud.ci.centos.org/buildStatus/icon?subject=CentOS%20CI%20-%20Arch%20(sanitizers)&job=upstream-vagrant-archlinux-sanitizers)](https://jenkins-systemd.apps.ocp.cloud.ci.centos.org/job/upstream-vagrant-archlinux-sanitizers/)<br/>
-[![CentOS CI - Rawhide (SELinux)](https://jenkins-systemd.apps.ocp.cloud.ci.centos.org/buildStatus/icon?subject=CentOS%20CI%20-%20Rawhide%20(SELinux)&job=upstream-vagrant-rawhide-selinux)](https://jenkins-systemd.apps.ocp.cloud.ci.centos.org/view/Upstream/job/upstream-vagrant-rawhide-selinux/)<br/>
 [![Fossies codespell report](https://fossies.org/linux/test/systemd-main.tar.gz/codespell.svg)](https://fossies.org/linux/test/systemd-main.tar.gz/codespell.html)</br>
 [![Weblate](https://translate.fedoraproject.org/widgets/systemd/-/master/svg-badge.svg)](https://translate.fedoraproject.org/engage/systemd/)</br>
 [![Coverage Status](https://coveralls.io/repos/github/systemd/systemd/badge.svg?branch=main)](https://coveralls.io/github/systemd/systemd?branch=main)</br>