Running plugin tests with Github Actions

I went on and took the oportunity of Trends and statistics extraction and added GitHub actions to this plugin today. It was pretty streight forward (thanks to @TimoGoebel pointing me to a @kamils-iRonin’s work). So far it runs smooth and it’s quite quick, especially if you cache the gems.

Any suggestions for improvements are welcome. There is not really complicated test suit yet, so it’s too soon to judge, but I’d like to implement it in other plugins as well if it prove its worth.
Anyone who’s opposed to that, please share your thoughts.