docs(tutorials): Add "stages" explicitly to the hook example

As mentioned here: #177 (comment), without the stages explicitly set, the hook always fails.

Author: matheuscas

docs/tutorials/auto_check.md

@@ -25,6 +25,7 @@ repos:
     rev: v1.17.0
     hooks:
       - id: commitizen
+        stages: [commit-msg]
 ```
 
 - Step 3: Install the configuration into git hook through `pre-commit`