Discrepancy in api-ref and code for create group type API

'name' is mentioned as an optional parameter in api-ref doc for
POST /v3/{project_id}/group_types API but in the code if we don't
pass 'name' it returns BadRequest. Also in create and update API,
'is_public' parameter is not added in api-ref document.

This patch fixes this discrepancy by updating the api-ref according
to the code.

Change-Id: I34e53ac72cbda9d8264e48e50f5a84ca09b850bd

api-ref/source/v3/group-types.inc

@@ -29,6 +29,7 @@ Request
    - group_type: group_type
    - name: name_16
    - description: description_12
+   - is_public: is_public_2
 
 Request Example
 ---------------
@@ -183,6 +184,7 @@ Request
    - group_type: group_type
    - name: name_16
    - description: description_12
+   - is_public: is_public_2
    - group_specs: group_specs
 
 Request Example

api-ref/source/v3/parameters.yaml

@@ -1396,6 +1396,12 @@ is_public_1:
   in: body
   required: false
   type: boolean
+is_public_2:
+  description:
+    Whether the group type is publicly visible.
+  in: body
+  required: false
+  type: boolean
 is_up:
   description: |
     Filter by up/down status.
@@ -1752,7 +1758,7 @@ name_16:
   description: |
     The group type name.
   in: body
-  required: false
+  required: true
   type: string
 name_17:
   description: |