Add timeout to CI checks

[bpkroth]

A python unit test failed in Github Action pipeline, but it took a long time:
https://github.com/microsoft/MLOS/pull/29/checks?check_run_id=1061557146#step:9:41362

We should see about controlling that with some timeouts.

[bpkroth]

As mentioned by @edcthayer this could also just be due to that particular run selecting a particularly complex polynomial that took longer to execute.

We could fix that individual check to restrict the polynomial complexity, but we should probably also set explicit limits on CI checks if we can.