disallow dashes in package names via package_scanner

[dom96]

No description provided.

[Yepoleb]

What should be done with the detected packages? Should I rename them with an underscore and add an alias?

[ringabout]

Yeah, rename or disable warnings for them. Whatever is easier to do should be the solution.

[Yepoleb]

We decided this needs to be discussed in an RFC because it only makes sense if we enforce package names to match module names, which is a much bigger change.