According to the scala-cli doc you can define a Repo like this:
//> using repository "https://maven-central.storage-download.googleapis.com/maven2"
And you can specify environment variables like this:
//> using publish.secretKey "env:PUBLISH_SECRET_KEY"
However there is no directive for repository.username, so I need something like
//> using repository "https://env:MYUSER:env:[email protected]"
Using the user and password directly works - but that is not really an option;).