Easily infer Flutter version from `pubspec.yaml` to avoid duplication about flutter-action

[braniii]

Until this feature is added, it can be achieved with GITHUB_ENV, e.g., if the pubspec.yaml contains

  flutter: ">=3.13.7"

The version can be extracted with:

    steps:
      - name: ⬇️ Checkout repository
        uses: actions/checkout@v3
      - name: Set Flutter version
        run: |
          export FLUTTER_VERSION="$(sed -E -n -e 's/^.*flutter:\ ">=([0-9.]+)"/\1/p' pubspec.yaml)"
          echo "FLUTTER_VERSION=$FLUTTER_VERSION" >> $GITHUB_ENV
      - name: ⚙️ Setup Flutter
        uses: subosito/flutter-action@v2
        with:
          flutter-version: "${{ env.FLUTTER_VERSION }}"
          channel: 'stable'
          cache: true
        id: flutter

For an example you can check my gh-action.yml

[subosito]

Until we have a standard definition in pubspec.yaml for flutter version, please use the yq and/or shell script, as @braniii mentioned.