Update README.md

Co-Authored-By: István Zoltán Szabó <[email protected]>

Author: ezimuel

README.md

@@ -113,7 +113,7 @@ Quickstart
 
 In elasticsearch-php, almost everything is configured by associative arrays. The REST endpoint, document and optional parameters - everything is an associative array.
 
-To index a document, we need to specify four pieces of information: index, id and a document body. This is done by
+To index a document, we need to specify three pieces of information: index, id and a document body. This is done by
 constructing an associative array of key:value pairs.  The request body is itself an associative array with key:value pairs
 corresponding to the data in your document: