Cancel simulation workflows when an update is pushed

[Thomasvdam]

Motivation

This saves some compute when frequently updating PRs.

Explanation of Changes

I used the same concurrency key that most other workflows are using.

Testing

Did not test, but since this works for other workflows I'm fairly confident it will work. Famous last words...

Related PRs and Issues

See the GHA runs for #214, simulation was not cancelled while test and interchaintest were when updates were pushed in quick succession.

[hacheigriega]

Thanks for this!!

A side question: I've been trying to fix the duplicate CI runs in the main of this repo. Do you think we should update the yml files to:

on:
  pull_request:
    push:
      branches:
        - main

as in the explorer ymls?

[Thomasvdam]

Which ones are running twice? With that config we can have tasks run only for PRs and not after a merge.

As discussed we'll add the update to only run certain workflows on PRs to this PR.

[hacheigriega]

Done!