title: How to update a subset of entities with ngrx-entity?
body: <p>I'm updating a set of entities using a HTTP Patch request to a remote backend. The response from the backend includes the updated entities only (i.e., not all entities).</p>
  
  <p>I set up my reducer with an entity state adapter and use <code>updateMany</code> to update my entities:</p>
  
  <pre><code>case settings.SettingsActionTypes.UpdateSettingsSuccess: {
     return {
       ...state,
       ...adapter.updateMany(action.payload.map((category) =&gt; Object.assign({}, {id: category.name, changes: category})), state),
       loaded: true,
       loading: false,
     }
   }
  </code></pre>
  
  <p>While this updates the entities that received an update, it deletes all others that are not returned by the backend.</p>
  
  <p>Is there a way to tell ngrx to only update entities that are included in the <code>action.payload</code>?</p>