Add Mac mini 2020 Xcode 13.1

[mlazari]

Checklist

If you have any non-Apple hardware components - submit your results to the Custom Hardware table.

• [X] I performed all steps to correctly run XcodeBenchmark.
• [X] I used Xcode 12.5 or above.
• [X] I attached a screenshot with a compilation time and other fields, example.
• [X] I confirm that Time column is still sorted.
• [X] The content in cells is centered.