actions/checkout upgraded to v4

Changelogs

Checklist:

[ ] Was this PR discussed in an issue? It is recommended to first discuss a new feature into a GitHub issue before opening a PR.
[ ] Add tests to cover the fixed bug(s) or the new introduced feature(s) (if appropriate).
[ ] Update the API documentation is a new function is added, or an existing one is deleted.
[ ] Write concise and explanatory changelogs below.
[ ] If possible, assign one of the following labels to the PR: feature, fix or test (or ask a maintainer to do it for you).

discussion related to that PR