[Security] Workflow docs.yml is using vulnerable action actions/checkout

The workflow docs.yml is referencing action actions/checkout using references v1. However this reference is missing the commit [a6747255bd19d7a757dbdda8c654a9f84db19839](https://github.com/actions/checkout/commits/a6747255bd19d7a757dbdda8c654a9f84db19839) which may contain fix to the some vulnerability.
The vulnerability fix that is missing by actions version could be related to:
(1) CVE fix
(2) upgrade of vulnerable dependency
(3) fix to secret leak and others.
Please consider to update the reference to the action.

Find the docs.yml workflow file in the .github/workflows directory. Update the actions/checkout reference from v1 to a secure version like v4. Verify the change by checking the GitHub Actions documentation for the latest secure tag. Running the workflow after the update will confirm it works.

Rédigé par le modèle d'indexation à partir du texte de l'issue.