`allow-newer` should not be used in CHaP

[lehins]

Using allow-newer should not be allowed in CHaP, at least not for the default version of ghc, which is 9.6 today.

Adding custom allow-newer, like it is done here should be reserved to individual projects and not the release platform, which is what CHaP is:

cardano-haskell-packages/nix/builder.nix

Lines 42 to 50 in 08a9d0e

	-- QuickCheck-2.16
	allow-newer: aeson:QuickCheck,
	tree-diff:QuickCheck,
	quickcheck-instances:QuickCheck,
	ral:QuickCheck,
	fin:QuickCheck,
	bin:QuickCheck,
	hedgehog-quickcheck:QuickCheck
	'';

Maintainers of libraries which are being released to CHaP should be responsible for compatibility issues using available tools like CPP, vendoring required changes from downstream dependencies or in an extreme cases release to CHaP of a fork with appropriate bounds fixed.

Hackage and Stackage are great examples. They will not allow packages to be added with unsolvable cabal build constraints, nor should we.