fix(deps): pin dependencies

This MR contains the following updates:

Package	Type	Update	Change
docker	service-image	pinDigest	→ 8bcbad4
docker	image	pinDigest	→ 8bcbad4
pytest (changelog)	dev	pin	^8.3.2 → 8.4.2
pytest-cov (changelog)	dev	pin	^5.0.0 → 5.0.0
registry.gitlab.developers.cam.ac.uk/uis/devops/lib/ucam-faas-python	final	pinDigest	→ 5d5373a
structlog (changelog)	dev	pin	^24.4.0 → 24.4.0

---

Configuration

📅 Schedule: Branch creation - Monday through Friday ( * * * * 1-5 ) in timezone Europe/London, Automerge - At any time (no schedule defined).

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

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

👻 Immortal: This MR will be recreated if closed unmerged. Get config help if that's undesired.

---

• If you want to rebase/retry this MR, check this box

---

This MR has been generated by Renovate Bot.