Build cabal-dev-scripts with ghc-9.8.1

[philderbeast]

Bumps aeson upper bounds so that cabal-dev-scripts builds with ghc-9.8.1. Also satisfies -Wunused-imports of (<>).

This can be tested with:

$ cabal repl gen-spdx --project-file=cabal.project.meta
$ make spdx --always-make
$ cabal build all --project-file=cabal.project.meta

Template Β: This PR does not modify cabal behaviour (documentation, tests, refactoring, etc.)

Include the following checklist in your PR:

• Patches conform to the coding conventions.

[philderbeast]

Label merge+no rebase is necessary when the pull request is from an organisation.