Update info for SketchupPerformance/OpenSSL

[thomthom]

https://forums.sketchup.com/t/how-to-generate-guid/155872/6?u=tt_su

https://rubocop-sketchup.readthedocs.io/en/latest/cops_performance/#sketchupperformanceopenssl

The Performance issue was addressed in SU2019 (double check) when the OpenSSL library that Ruby uses was updated with one that included a fix for the performance issue.

• Add information to the cop description
• Allow the cop to use the TargetSketchUpVersion and warn only when the target includes affected versions of SketchUp.