Update docker/dockerfile Docker tag to v1.7

[renovate[bot]]

This PR contains the following updates:

Package	Type	Update	Change
docker/dockerfile	syntax	minor	1.4 -> 1.7

---

Configuration

📅 Schedule: Branch creation - "before 4pm on Wednesday except before 9am on Wednesday" in timezone America/New_York, 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 has been generated by Mend Renovate. View repository job log here.