Merge pull request #6950 from phadej/changelog-3.4

Cabal/Distribution/Compat/DList.hs

Cabal/Distribution/Compat/NonEmptySet.hs

Cabal/Distribution/Simple/GHC.hs

Cabal/Distribution/Types/Dependency.hs

Cabal/Distribution/Types/Mixin.hs

Cabal/Distribution/Types/PackageVersionConstraint.hs

Cabal/Distribution/Types/SourceRepo.hs

Cabal/Distribution/Verbosity.hs

Cabal/Distribution/Verbosity/Internal.hs

changelog.d/Cabal-QuickCheck

changelog.d/Cabal-tree-diff

changelog.d/PerCompilerFlavor-functor

changelog.d/active-repositories

changelog.d/added-tests

changelog.d/backported

changelog.d/build-reports

changelog.d/cabal-init

changelog.d/cabal-list

changelog.d/cabal-project-local-tilde

changelog.d/cabal-sdist