mac based testing

[j-i-l]

This is needed to complete the complete the selection of platforms we want to test.

Since running OSX in a container is not straight forward, we setup the environment directly on a github M1 runner in a separate workflow.

[j-i-l]

There is actually no mac container on r-hub (neither is there one for windows).

R-hubs approach for OSX consists in using OSX IaaS, so to rent some Mac Mini servers somewhere.

Since January 24, github offers M1 MacOS runners (see announcement) which could be used to directly in the repository to test.

What we could do here is prepare a composite action that installs the needed dependencies (here is how one can install additional packages on a macos runner).

Alternatively, there are some (1, 2) ways to build OSX based container, however, they rely on KVM, which is not supported by the regular GitHub runners, it seems.

We should decide how we want to proceed hers.

[j-i-l]

Decision

We build a workflow to configure install and check abn on the M1 osx runner.

A good example can be found on r-lib