Don't publish empty scala-library:%dotty-version%

[tgodzik]

Currently an empty jar is being published along the compiler which is called scala-compiler:%dotty-version% - scala-compiler:0.23 etc.

The explanation is given that it is in order to make sure some tools don't break when working with Dotty. I believe this only hides the issues for those tools and might cause more issues in the long run.

For example when trying to work with Mill some users reported that the code doesn't compile with Bloop: scalameta/metals#1768
After some investigation it turned out there might be some logic in Zinc/Bloop that searches for scala-library and finds the empty jar instead of the actual scala-library:2.13.1. Without the additional jar, this would quickly come up and could be fixed inside Mill. Instead, we needed to spend more time on investigating this.

I think it doesn't make sense anymore to publish it.