docs: add target

Author: dc7290

README.md

@@ -109,7 +109,8 @@ client
 #### Get all content ids
 
 This function can be used to retrieve all content IDs only.  
-Since `filters` and `draftKey` can also be specified, it is possible to retrieve only the content IDs for a specific category, or to include content from a specific draft.
+Since `filters` and `draftKey` can also be specified, it is possible to retrieve only the content IDs for a specific category, or to include content from a specific draft.  \
+The `target` property can also be used to address cases where the value of a field other than content ID is used in a URL, etc.
 
 ```javascript
 client
@@ -136,6 +137,16 @@ client
   })
   .then((res) => console.log(res))
   .catch((err) => console.error(err));
+
+// Get all content ids with target
+client
+  .getAllContentIds({
+    endpoint: 'endpoint',
+    target: 'url',
+  })
+  .then((res) => console.log(res))
+  .catch((err) => console.error(err));
+```
 ```
 
 #### CREATE API