WIP: Update gitlab_git to 10.6.10

What does this MR do?

Bring the improvements of gitlab_git 10.6.9 and 10.6.10 to gitlab-ce

Are there points in the code the reviewer needs to double check?

No

Does this MR meet the acceptance criteria?

• CHANGELOG entry added
• 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 #23645 (closed)