Update actions/cache action to v6

[renovate]

This PR contains the following updates:

Package	Type	Update	Change	Pending
actions/cache	action	major	v5.0.5 → v6.0.0	v6.1.0

---

Release Notes

actions/cache (actions/cache)

v6.0.0

Compare Source

What's Changed

• Update packages, migrate to ESM by @​Samirat in #​1760

Full Changelog: actions/cache@v5...v6.0.0

v6

Compare Source

v5.1.0

Compare Source

What's Changed

• Bump @​actions/cache to v5.1.0 - handle read-only cache access by @​jasongin in #​1775

Full Changelog: actions/cache@v5...v5.1.0

---

Configuration

📅 Schedule: (UTC)

• Branch creation
  • At any time (no schedule defined)
• Automerge
  • At any time (no schedule defined)

🚦 Automerge: Enabled.

♻ Rebasing: Whenever PR is behind base branch, 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 was generated by Mend Renovate. View the repository job log.

[github-actions]

End-to-end public repo

Admin commands cheatsheet:

• /e2e (in approved PR review body): Trigger end-to-end tests on external contributions
• /invite (in comment): Invite the author & admins to the end-to-end private repo

[github-actions]

Coverage report

This PR does not seem to contain any modification to coverable code.