Try to cancel PR build after merge
Try to cancel PR build after merge

This migrates cleanup from
https://github.com/marketplace/actions/cancel-previous-workflow-runs to
https://github.com/marketplace/actions/cancel-workflow-action.

It has not been tested whether this actually does what it is supposed to
do.

ebyhr/presto,Praveen2112/presto,ebyhr/presto,losipiuk/presto,dain/presto,dain/presto,dain/presto,smartnews/presto,ebyhr/presto,ebyhr/presto,losipiuk/presto,Praveen2112/presto,smartnews/presto,11xor6/presto,losipiuk/presto,smartnews/presto,11xor6/presto,smartnews/presto,11xor6/presto,11xor6/presto,Praveen2112/presto,losipiuk/presto,Praveen2112/presto,dain/presto,losipiuk/presto,11xor6/presto,dain/presto,smartnews/presto,Praveen2112/presto,ebyhr/presto