Update README.md

Author: picandocodigo

elasticsearch-api/utils/README.md

@@ -26,7 +26,7 @@ $ IGNORE_VERSION=true thor code:generate
 
 - You can use the environment variable `BUILD_HASH` to update the build hash for the generated code from the `tmp/rest-api-spec/build_hash` file. This file is updated every time you use the `elasticsearch:download_artifacts` Rake task is used in the root of the project to download the latest Elasticsearch specs and tests:
 ```bash
-$ IGNORE_VERSION=true thor code:generate
+$ BUILD_HASH=true thor code:generate
 ```
 
 ### Development