Update rouge gem version

What does this MR do and why?

Update rouge gem to resolve #347277 (closed).

How to set up and validate locally

See steps to reproduce in #347277 (closed)

Screenshots

Example from #347277 (closed) now renders in sub-second time:

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.