Setting Flutter environment based on FVM

[Gj1337]

FVM is a quite popular tool for managing Flutter SDK. A lot of projects use FVM and it would be a great to have opportunity establish Flutter based on FVM config.

Something like

steps:
  - name: Clone repository
    uses: actions/checkout@v4
  - name: Set up Flutter
    uses: subosito/flutter-action@v2
    with:
      use_fvm: true
  - run: fvm flutter --versios