Use facebook mirror for CentOS Stream 8

Current mirror http://mirror.dal10.us.leaseweb.net/centos/8-stream
is hitting issues and is impacting all CS8 jobs.

Switching to facebook mirror fixes the issue.

Related-Bug: #1958510

Signed-off-by: Chandan Kumar (raukadah) <chkumar@redhat.com>
Change-Id: Ibddbee60c4318fd7bd34f281af95a20bf172c572

playbooks/roles/mirror-update/files/centos-mirror-update

@@ -39,7 +39,7 @@ K5START="k5start -t -f /etc/centos.keytab service/centos-mirror -- $TIMEOUT"
 # -- Centos 8-stream --
 #
 
-MIRROR=rsync://mirror.dal10.us.leaseweb.net/centos/8-stream/ # somewhere in TX
+MIRROR=rsync://mirror.facebook.net/centos/8-stream/ # somewhere in US
 
 if ! [ -f $BASE/8-stream ]; then
     $K5START mkdir -p $BASE/8-stream