Update actions/checkout action to v3

[renovate]

This PR contains the following updates:

Package	Type	Update	Change
actions/checkout	action	major	v2 -> v3

---

⚠ Dependency Lookup Warnings ⚠

Warnings were logged while processing this repo. Please check the Dependency Dashboard for more information.

---

Release Notes

actions/checkout

v3

Compare Source

• Add input set-safe-directory

---

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, click this checkbox.

---

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

[0crat]

There is an unrecoverable failure on my side. Please, submit it here:

PID: 4@ed544f0b-561e-4dc6-a94b-4a0206b914fb, thread: PQ-C3RUBL5H9
com.jcabi.xml.StrictXML[124] java.lang.IllegalArgumentException: 2 error(s) in XML document: -1:-1: cvc-pattern-valid: Value 'renovate[bot]' is not facet-valid with respect to pattern '[a-z0-9\-]{3,}' for type 'login'.;-1:-1: cvc-type.3.1.3: The value 'renovate[bot]' of element 'login' is not valid.

1.0-SNAPSHOT: CID: 286d9685-9108-4aa3-83bb-cba25c8c171e, Type: "Job was added to WBS"

[0crat]

@yegor256/z everybody who has role REV is banned at #362; I won't be able to assign anyone automatically; consider assigning someone manually (as in §19), or invite more people (as in §51), or remove the job from the scope (as in §14)

[0crat]

Job gh:jcabi/jcabi-http#362 is not assigned, can't get performer