Minor Discussion template updates

Author: michaelklishin

.github/DISCUSSION_TEMPLATE/ideas.yml

@@ -16,7 +16,6 @@ body:
     attributes:
       label: RabbitMQ series
       options:
-        - 3.13.x
         - 4.0.x
         - 4.1.x
     validations:

.github/DISCUSSION_TEMPLATE/other.yml

@@ -23,10 +23,8 @@ body:
     attributes:
       label: RabbitMQ version used
       options:
-        - 4.0.2
-        - 3.13.7
-        - 3.13.6
-        - 3.12.x or older
+        - 4.0.3
+        - 3.13.7 or older
     validations:
       required: true
   - type: dropdown

.github/DISCUSSION_TEMPLATE/questions.yml

@@ -27,10 +27,8 @@ body:
     attributes:
       label: RabbitMQ version used
       options:
-        - 4.0.2
-        - 3.13.7
-        - 3.13.6
-        - 3.12.x or older
+        - 4.0.3
+        - 3.13.7 or older
     validations:
       required: true
   - type: dropdown