feat: add new generation of nodepools (#7586)

Author: agoose77

eksctl/nmfs-openscapes.jsonnet

@@ -24,7 +24,7 @@ local c = cluster.withNodeGroupConfigOverride(
         instanceType: 'g4dn.xlarge',
       },
     ],
-    nodeGroupGenerations=['a', 'b'],
+    nodeGroupGenerations=['b', 'c'],
   ),
   kind='core',
   overrides={ maxSize: 2 }