Switch centos-8 jobs to centos-8-stream

Depends-On: https://review.opendev.org/797069

Change-Id: Ic80b256f771a7e61d2714644852cffb5271b1612
diff --git a/zuul.d/projects.yaml b/zuul.d/projects.yaml
index b3782b9..f872c59 100644
--- a/zuul.d/projects.yaml
+++ b/zuul.d/projects.yaml
@@ -23,7 +23,7 @@
         - octavia-v2-dsvm-tls-barbican-stable-train
         - octavia-v2-dsvm-scenario-ipv6-only:
             voting: false
-        - octavia-v2-dsvm-scenario-centos-8:
+        - octavia-v2-dsvm-scenario-centos-8-stream:
             voting: false
         - octavia-v2-act-stdby-dsvm-scenario-two-node:
             voting: false