Update gitlab shell

What does this MR do?

Updates GitLab Shell to v8.3.2, fixing a ~bug and a regression:11.3

CHANGELOG can be seen here: gitlab-shell!243 (diffs)

What are the relevant issue numbers?

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• Documentation created/updated
• Tests added for this feature/bug
• Conforms to the code review guidelines
• Conforms to the merge request performance guidelines
• Conforms to the style guides
• Conforms to the database guides