Update centos8 mirrors

Signed-off-by: Evan Lezar <elezar@nvidia.com>

docker/Dockerfile.centos

@@ -1,6 +1,14 @@
 ARG BASEIMAGE
 FROM ${BASEIMAGE}
 
+ARG BASEIMAGE
+# See https://www.centos.org/centos-linux-eol/
+# and https://stackoverflow.com/a/70930049
+RUN [[ "${BASEIMAGE}" != "centos:8" ]] || \
+    ( \
+      sed -i 's/mirrorlist/#mirrorlist/g' /etc/yum.repos.d/CentOS-Linux-* && \
+      sed -i 's|#baseurl=http://mirror.centos.org|baseurl=http://vault.centos.org|g' /etc/yum.repos.d/CentOS-Linux-* \
+    )
 RUN yum install -y \
         ca-certificates \
         wget \