Show "Add dependency" Code Action only if there is no package.yaml file #4400
Description
If the project is a stack project, there might be a package.yaml file. Adding a dependency to the generated .cabal file is a bad idea, as it will lead to annoying behaviour: Stack will no longer re-generate the .cabal file, so changes to package.yaml are not propagated to the .cabal file any more.
solution:
When looking for the .cabal file in the filesystem, check there is no package.yaml file next to it.