Consider evaluating SSIMULACRA against CLIC 2021 data

See the [similar issue](https://github.com/libjxl/libjxl/issues/202) in libjxl .

It would be great to evaluate SSIMULACRA on the CLIC-2021 perceptual quality task. This should provide additional information to he community with respect to its performance characteristics when compared to other potentially usable perceptual quality metrics.

Please use the test data from the CLIC 2021 perceptual challenge to generate a CSV file with the decisions (see link below for the exact instructions):

https://github.com/fab-jul/clic2021-devkit/blob/main/README.md#perceptual-challenge

Please email them to George Toderici (or me) to get the final results / ranks. We'll publish these at: http://compression.cc/leaderboard/perceptual/test/

...and of course update this bug tracker.