Use of `actions/checkout@v2` [generates warnings](https://github.com/spring-projects/spring-authorization-server/actions/runs/4387393970) in GitHub Actions. We should switch to [`actions/checkout@v3`](https://github.com/marketplace/actions/checkout).
Use of
actions/checkout@v2generates warnings in GitHub Actions. We should switch toactions/checkout@v3.