Update rouge

What does this MR do?

Update rouge to 3.4 which has a bunch of nice new things

changelog

I don't think there are any risks or any additional test cases necessary.

Does this MR meet the acceptance criteria?

Conformity

Not sure if any of the below are necessary. Maybe. I'm just looking forward to this fixing our Perl syntax highlighting.

• Changelog entry
• Documentation created/updated or follow-up review issue created
• Code review guidelines
• Merge request performance guidelines
• Style guides
• Database guides
• Separation of EE specific content