concurrency github action run is causing failure

[lianhao]

Our current github action will cause failure when multiple runs are triggered in parallel. E.g. when jobs run in the following sequence, error happens:

1. PR fix: hotelReservation README file subheading typo #242 triggered hotelReservation workflow run 3577351936
2. PR HotelReservation: multiple bug fixings and enhancement #247 triggeredhotelReservation workflow run 3577352616.
3. Run 3577351936 finished the job 'Calculate new version' and got the result of new version hotelReservation-0.0.2.
4. Run 3577352616 finished the job 'Calculate new version' and got the result of new version hotelReservation-0.0.2.
5. Run 3577351936 finished the job 'Create tag' and created a new tag hotelReservation-0.0.2.
6. Job 'Create tag' of run 3577352616 failed, because the tag hotelReservation-0.0.2 it wanted to create was already existing. See https://github.com/delimitrou/DeathStarBench/actions/runs/3577352616/jobs/6016248939.