chore(deps): update src/ovpn-dco digest to c4c4f80 (release/2.6)

[openvpn-inc-ci]

This PR contains the following updates:

Package	Update	Change
src/ovpn-dco	digest	2aa7f93 -> c4c4f80

---

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 Renovate Bot.