Add the update button for a task.

templates/partials/task_form.html

@@ -4,6 +4,10 @@
   <form method="POST">
     {% csrf_token %}
     {{ task_form|crispy }}
-    <button type="submit" hx-post=".">Submit</button>
+    {% if task %}
+      <button type="submit" hx-post="{% url 'tasks:task-update' task.id %}">Submit</button>
+    {% else %}
+      <button type="submit" hx-post=".">Submit</button>
+    {% endif %}
   </form>
 </div>