feat: support pnpm install

[yusuke99]

Closes #27

Add an optional pnpm input so workflows can install pnpm globally, allowing executable path which makes running pnpm command available. It is defaulted to false.

Usage:

- uses: voidzero-dev/setup-vp@1.18.0
  with:
    pnpm: true

I have verified that my fork's CI have passed and executable path is available.

If you want to verify GitHub Actions locally via act, here's how 👇

*Make sure Docker is running to test with act

.github/workflows/test.yml

test-pnpm:
  strategy:
    fail-fast: false
    matrix:
      os: [ubuntu-latest, macos-latest, windows-latest]
  runs-on: ${{ matrix.os }}
  steps:
    # 👇 Make sure this is commented so that you can test this locally
    # - uses: taiki-e/checkout-action@7d1e50e93dc4fb3bba58f85018fadf77898aee8b # v1.4.2

    - name: Setup Vite+ with global pnpm
      uses: ./
      with:
        pnpm: true
        run-install: false
        cache: false

    - name: Verify pnpm is installed globally
      shell: bash
      run: |
        global_list="$(vp list -g pnpm)"
        echo "$global_list"
        if [[ "$global_list" == *"No global packages matching 'pnpm'"* ]]; then
          echo "pnpm was not installed globally" >&2
          exit 1
        fi
        pnpm --version

Run the following:

act push \                    
  -W ".github/workflows/test.yml" \
  -j test-pnpm \
  --matrix os:ubuntu-latest \
  -P ubuntu-latest=catthehacker/ubuntu:act-latest \
  --pull=false \
  --bind

Referece: https://github.com/nektos/act

setup-vp.mp4