Drop older EOL opensuse versions

roles/netbootxyz/defaults/main.yml

@@ -376,14 +376,6 @@ releases:
     versions:
     - code_name: '15.3'
       name: openSUSE Leap 15.3
-    - code_name: '15.2'
-      name: openSUSE Leap 15.2
-    - code_name: '15.1'
-      name: openSUSE Leap 15.1
-    - code_name: '15.0'
-      name: openSUSE Leap 15.0
-    - code_name: '42.3'
-      name: openSUSE Leap 42.3
     - code_name: tumbleweed
       name: openSUSE tumbleweed
   oracle: