Add openSUSE 15.4

roles/netbootxyz/defaults/main.yml

@@ -374,6 +374,8 @@ releases:
     mirror: http://download.opensuse.org
     name: OpenSUSE
     versions:
+    - code_name: '15.4'
+      name: openSUSE Leap 15.4   
     - code_name: '15.3'
       name: openSUSE Leap 15.3
     - code_name: tumbleweed