[Haskell-cafe] stack and package candidates

[Henning Thielemann]

In a project my stack.yaml contains this line:

- url: https://hackage.haskell.org/package/foobar-0.0/candidate/foobar-0.0.tar.gz

This works, but if I update the foobar release candidate then Stack will 
not notice and stick to the old version. How can I invalidate or remove 
the cached foobar version?