Fix merge conflict size limit

What does this MR do?

The merge conflict size limit was set to 100 KB, but the docs (and the test repo, which the feature specs use) say 200 KB!

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

Don't think so.

Why was this MR needed?

Derp.

Does this MR meet the acceptance criteria?

• CHANGELOG entry added
• Documentation created/updated
• Tests
  • Added for this feature/bug
  • All builds are passing
• Conform by the style guides
• Branch has no merge conflicts with master (if you do - rebase it please)
• Squashed related commits together