Benchmark Run Concurrency Queues

[stanbrub]

With more developer (i.e. more than me) using adhoc benchmarks and more ways to run them, there is a possibility of stomping over existing runs when the same server is used for two runs. This is not a problem for auto-provisioned servers where a unique server is used for every adhoc run.

Resources:

• https://docs.github.com/en/actions/writing-workflows/choosing-what-your-workflow-does/control-the-concurrency-of-workflows-and-jobs