Why foldl < 1.1?

[gibiansky]

This makes it harder to compile with stackage nightly! Any particular reason for this upper bound?

[GregorySchwartz]

Current guildlines suggest to have these upper bounds to prevent breakages (it's better to change a cabal file value than fix compiling errors and changing APIs). I bumped the dependency.

https://wiki.haskell.org/Package_versioning_policy