MS Windows: Figure out how to run Bats, e.g. via git Bash

[HenrikBengtsson]

Bats support MS Windows via various Bash alternatives, cf.

• https://bats-core.readthedocs.io/en/stable/support-matrix.html#supported-operating-systems
• https://bats-core.readthedocs.io/en/stable/installation.html#windows-installing-bats-from-source-via-git-bash

Tasks:

Figure out how to do this on

• [ ] a local MS Windows machine (e.g. VM)
• [ ] GitHub Actions