Relax constraint on prettyprinter

[sjakobi]

Closes #5094.

Checklist:

• Meaningful commit message, eg add my-cool-package (please not mention build-constraints.yml)

• At least 30 minutes have passed since uploading to Hackage

• On your own machine, in a new directory, you have successfully run the following set of commands (replace $package with the name of the package that is submitted, and $version with the version of the package you want to get into Stackage):

  stack unpack $package-$version  # $version is optional
  stack init --resolver nightly
  stack build --resolver nightly --haddock --test --bench --no-run-benchmarks
  

[sjakobi]

The CI failure looks unrelated:

ghc-lib-parser-ex-8.8.3.0 (Shayne Fletcher <[email protected]>) is out of bounds for:
- [ ] hlint-2.2.8 (==8.8.2). Neil Mitchell <[email protected]> @ndmitchell. @ndmitchell. Used by: library

[juhp]

Oops, sorry for not reading ahead, should be in the next nightly

[sjakobi]

No worries. Thank you @juhp! :)