Update CI config, adding GHC 9.6 jobs

[Bodigrim]

Inspection tests fail on GHC 9.6, because M1 survives in types:

        lvl_soCG
          :: M1
               C
               ('MetaCons "Never" 'PrefixI 'False)
               (S1
                  ('MetaSel
                     'Nothing 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy)
                  (Rec0 Void))
               Any
        lvl_soCG
          = case error (lvl_soSv `cast` <Co:4> :: ...) lvl_soSx of wild_00 {
            }

        lvl_soTe :: MyAction
        lvl_soTe = Never (lvl_soCG `cast` <Co:43> :: ...)

This is quite irrelevant, data MyAction = Code (Maybe Bool) | Never Void | Eat (Bool, Bool) | Sleep () and we do not really care about optimization of error :: Void, but I'm unsure what's the best way to mute this test.

[Bodigrim]

I think this is good to go now.