update Scientific Linux Version

roles/netbootxyz/defaults/main.yml

@@ -426,14 +426,14 @@ releases:
     mirror: http://ftp1.scientificlinux.org
     name: Scientific Linux
     versions:
+    - code_name: '7.9'
+      name: '7.9'
+    - code_name: '7.8'
+      name: '7.8'
     - code_name: '7.7'
       name: '7.7'
     - code_name: '7.6'
       name: '7.6'
-    - code_name: '6.10'
-      name: '6.10'
-    - code_name: '6.9'
-      name: '6.9'
   slackware:
     base_dir: slackware
     enabled: true