[skip ci] Add 4.0.6 an 4.0.7 to the discussion template

Author: mkuratczyk

.github/DISCUSSION_TEMPLATE/questions.yml

@@ -29,6 +29,8 @@ body:
     attributes:
       label: RabbitMQ version used
       options:
+        - 4.0.7
+        - 4.0.6
         - 4.0.5
         - 4.0.4
         - 4.0.3