Evaluate Flank on WSL 2

[bootstraponline]

Author the user story for this feature

As a Flank user, I want to run Flank on windows using WSL so I can run tests on Windows.

Describe the solution you'd like

Flank's test suite should run via WSL 2. If it works, then we'd update the documentation to mention how to run Flank via WSL on Windows.

Describe alternatives you've considered

Running Flank natively on Windows is too different from macOS and Linux. This isn't being considered at this time.

[bootstraponline]

• https://github.com/marketplace/actions/setup-wsl
• https://github.com/actions/virtual-environments/issues
• https://docs.github.com/en/actions/reference/specifications-for-github-hosted-runners#about-github-hosted-runners
• Add Windows Subsystem for Linux to Windows actions/runner-images#50