Docs: Add docatl alternative for update index

fixes: #320, #322

Author: reglim

README.md

@@ -141,4 +141,11 @@ You can force the index re-creation using the following request:
 ```sh
 curl -X POST http://localhost:8000/api/index/update
 ```
+
+Using `docatl`:
+
+```sh
+docatl update-index --host http://localhost:8000
+```
+
 Don't worry if it takes some time :)

doc/getting-started.md

@@ -179,4 +179,10 @@ To force the re-creation of the search index, you can use the following command:
 curl -X POST http://localhost:8000/api/index/update
 ```
 
+Using `docatl`:
+
+```sh
+docatl update-index --host http://localhost:8000
+```
+
 Note that this can take some time.