Update codecov/codecov-action action to v4

[renovate[bot]]

This PR contains the following updates:

Package	Type	Update	Change
codecov/codecov-action	action	major	v3 -> v4

---

Release Notes

codecov/codecov-action (codecov/codecov-action)

### [`v4`](https://togithub.com/codecov/codecov-action/compare/v3...v4) [Compare Source](https://togithub.com/codecov/codecov-action/compare/v3...v4)

---

Configuration

📅 Schedule: Branch creation - At any time (no schedule defined), Automerge - At any time (no schedule defined).

🚦 Automerge: Disabled by config. Please merge this manually once you are satisfied.

♻ Rebasing: Whenever PR becomes conflicted, or you tick the rebase/retry checkbox.

🔕 Ignore: Close this PR and you won't be reminded about this update again.

---

• [ ] If you want to rebase/retry this PR, check this box

---

This PR has been generated by Mend Renovate. View repository job log here.

[yegor256]

@rultor please, try to merge, since 8 checks have passed

[rultor]

@rultor please, try to merge, since 8 checks have passed

@yegor256 OK, I'll try to merge now. You can check the progress of the merge here

[rultor]

@rultor please, try to merge, since 8 checks have passed

@yegor256 Done! FYI, the full log is here (took me 5min)