Fix missing schema

Author: d-yoshi

src/openapi.yml

@@ -9,7 +9,7 @@ info:
   license:
     name: MIT
     url: https://github.com/d-yoshi/redmine-openapi/blob/main/LICENSE
-  version: 0.9.0
+  version: 0.9.1
 
 servers:
   - url: /

src/paths/memberships.membership_id.yml

@@ -33,6 +33,23 @@ put:
     - $ref: ../components/parameters/path/format.yml
     - $ref: ../components/parameters/path/membership_id.yml
     - $ref: ../components/parameters/header/x_redmine_switch_user.yml
+  requestBody:
+    content:
+      application/json:
+        schema:
+          type: object
+          required:
+            - membership
+          properties:
+            membership:
+              type: object
+              required:
+                - role_ids
+              properties:
+                role_ids:
+                  type: array
+                  items:
+                    type: integer
   responses:
     204:
       description: ""