feat: Add GitHub actions packager option

[appfr3d]

Description

This PR automatically detects the packager and package runner to use when running react-native-harness in GitHub Actions, based on the lock file available in the repo.

Related Issue

N/A

Context

I really like the react-native-harness library, and just started using it on a clients project. That project uses npm and not pnpm which is currently hardcoded into the GitHub Actions. Since your "Getting started" guides suggest that this library supports multiple different packagers, I created this PR to make the GitHub Actions also support different packagers.

Testing

Not sure how to test this change, but it passes pnpm test:all and pnpm typecheck:all.
Also tested on clients GitHub Actions by referencing the fork like this
uses: appfr3d/react-native-harness/actions/ios@github-actions-packager-option

[vercel]

@appfr3d is attempting to deploy a commit to the Callstack Team on Vercel.

A member of the Team first needs to authorize it.

[V3RON]

Wouldn't it be easier to just have a short shell script that checks the working directory, figures out which lockfile is present, and sets a variable based on that? Then we can use that variable in the next step to run Harness.

- name: Detect Package Manager
    id: detect-pm
    run: |
      if [ -f "pnpm-lock.yaml" ]; then
        echo "manager=pnpm" >> $GITHUB_OUTPUT
        echo "runner=pnpm exec" >> $GITHUB_OUTPUT
      elif [ -f "yarn.lock" ]; then
        echo "manager=yarn" >> $GITHUB_OUTPUT
        echo "runner=yarn" >> $GITHUB_OUTPUT
      elif [ -f "bun.lockb" ]; then
        echo "manager=bun" >> $GITHUB_OUTPUT
        echo "runner=bun x" >> $GITHUB_OUTPUT
      else
        echo "manager=npm" >> $GITHUB_OUTPUT
        echo "runner=npx" >> $GITHUB_OUTPUT
      fi

  - name: Run CLI Tool
    run: ${{ steps.detect-pm.outputs.runner }} react-native-harness

[appfr3d]

Seems like dx is the new npx in deco-land, but it is quite new so I can change to deno run -A npm: if desired.
Ref: https://deno.com/blog/v2.6