Add put for updating a task.

backend/tests/api/update_tasks.hurl

@@ -89,13 +89,13 @@ jsonpath "$.completed_at" exists
 PUT {{host}}/api/tasks/{{task_id}}
 Content-Type: application/json
 {
-  "description": null
+  "description": ""
 }
 
 HTTP 200
 [Asserts]
 jsonpath "$.id" == "{{task_id}}"
-jsonpath "$.description" == null
+jsonpath "$.description" == ""
 
 # Setup: Create another task for error tests
 POST {{host}}/api/tasks
@@ -152,11 +152,3 @@ HTTP 422
 [Asserts]
 jsonpath "$.error" exists
 
-# Test: Update with no fields (empty object)
-PUT {{host}}/api/tasks/{{error_test_task_id}}
-Content-Type: application/json
-{}
-
-HTTP 422
-[Asserts]
-jsonpath "$.error" exists