Bump Gitlab-Shell to 5.4.0

Why was this MR needed?

Gitaly is deprecating old naming scheme for Services. This updates Shell to use the new naming scheme

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• Documentation created/updated
• API support added
• Tests
  • Added for this feature/bug
  • All builds are passing
• Conform by the merge request performance guides
• Conform by the style guides
• Branch has no merge conflicts with master (if it does - rebase it please)
• Squashed related commits together

What are the relevant issue numbers?

Closes gitaly#381 (closed)