building ghcup with ghc-9.6/transformers-0.6

[juhp]

I got close to be able to cabal build Hackage ghcup-0.1.30 with ghc-9.6 (ie close to lts-22 level package set), until I hit:

lib/GHCup/Utils/Parsers.hs:141:33: error: [GHC-39999]
    • No instance for ‘GHC.Base.Alternative (Either String)’
        arising from a use of ‘<|>’
    • In the first argument of ‘(<|>)’, namely
        ‘second ToolDay (dayParser s') <|> second ToolTag (tagEither s')’
      In the expression:
        second ToolDay (dayParser s') <|> second ToolTag (tagEither s')
          <|> second GHCVersion (ghcVersionEither s')
      In an equation for ‘ghcVersionTagEither’:
          ghcVersionTagEither s'
            = second ToolDay (dayParser s') <|> second ToolTag (tagEither s')
                <|> second GHCVersion (ghcVersionEither s')
    |
141 |   second ToolDay (dayParser s') <|> second ToolTag (tagEither s') <|> second GHCVersion (ghcVersionEither s')
    |                                 ^^^

Maybe related: https://gitlab.haskell.org/ghc/ghc/-/wikis/migration/9.6#transformers-06-error-a--alternative-either-a-and-error-a--monadplus-either-a-instances-removed

[hasufell]

See #1127

[juhp]

Thanks - ed0fd9b seems to do the trick for me.