feat(errors): 401 might be returned by the API-Gateway

spec/endpoints/destinations/index.yml

@@ -21,12 +21,19 @@ get:
           examples:
             example-1:
               $ref: '../../examples/destination-list.yml'
+    '401':
+      description: Unauthorized
+      content:
+        application/problem+json:
+          schema:
+            $ref: '../../schemas/error.yml'
     '403':
       description: Forbidden
       content:
         application/problem+json:
           schema:
             $ref: '../../schemas/error.yml'
+
 post:
   operationId: create-destination
   summary: Zustellpunkt anlegen