Test workflow fails if pre-commit step makes changes to forked repo

[cjfullerton]

This seems to be a permissions issue.

workaround: run test workflow on branch on forked repo manually. Changes are made during this, so test stage of release doesn't fail.

[cjfullerton]

jobs:
  pre-commit:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v3
        with:
          # PAT of user who has permission to bypass branch
          # protection || or standard GITHUB_TOKEN if running on an external fork (won't
          # be able to commit fixes):
          token: {{ '${{' }} secrets.{{ token_name }} {{ '|| secrets.GITHUB_TOKEN }}' }}
          # checkout PR source branch (head_ref) if event is pull_request:
          ref: {% raw %}${{ github.head_ref || github.ref }}{% endraw %}
          repository: {% raw %}${{ github.event.pull_request.head.repo.full_name }}{% endraw %}

[dkfellows]

See hpcflow/matflow#283