Bump container registry to v3.18.0

What does this MR do?

3.18.0 (2021-12-09)

Bug Fixes

• datastore: do not panic if database credentials are wrong (cfc51e7)

Features

• datastore: calculate deduplicated repository size (#486 (closed)) (86d68c1)
• datastore: enable PostgreSQL pageinspect extension (74f6521)
• datastore: extend support for Helm Charts media types (ff2fd80)
• gc: add dangling and event labels to online GC run metrics (738cf24)
• gc: log creation timestamp and event of GC tasks (e0133c3)

Related issues

Related to gitlab-org/container-registry#531 (closed).

Checklist

See Definition of done.

For anything in this list which will not be completed, please provide a reason in the MR discussion

Required

• Merge Request Title, and Description are up to date, accurate, and descriptive
• MR targeting the appropriate branch
• MR has a green pipeline on GitLab.com

Expected (please provide an explanation if not completing)

• Test plan indicating conditions for success has been posted and passes
• Documentation created/updated
• Integration tests added to GitLab QA
• The impact any change in container size has should be evaluated