This action cleans up previously running instances of a workflow on the same branch. This accomplishes the task of automatically cancelling CI runs on pushes to the same branch, which is a common feature in most CI systems but currently not possible with GitHub actions.

None. The action uses the GitHub action environment variables to obtain the workflow name and branch. You must, however, set the GITHUB_TOKEN environment variable:

uses: rokroskar/workflow-run-cleanup-action
env:
  GITHUB_TOKEN: ${{ secret.GITHUB_TOKEN }}

You may want to disable this action from running on tags or master, especially if you have CD pipelines linked to your CI passing on every commit. In that case, something like this should work:

name: CI
on:
  push: []
  jobs:
    cleanup-runs:
      runs-on: ubuntu-latest
      steps:
      - uses: rokroskar/workflow-run-cleanup-action@master
        env:
          GITHUB_TOKEN: "${{ secrets.GITHUB_TOKEN }}"
      if: "!startsWith(github.ref, 'refs/tags/') && github.ref != 'refs/heads/master'"
    ...
    other-jobs: