Remove 'show-build-info' from lib:Cabal

[Fendor]

Hello everyone!

The lib:Cabal (Setup.hs) command 'show-build-info' is going to be 
removed with the next
Cabal version (3.8). It is being replaced by the build flag 
'--enable-build-info' that is added
to 'build' directly.
If you depend on 'show-build-info' in any way, please give us feedback 
on [1] or [2].

Details on the purpose and implementation of 'show-build-info' can be 
found here: [1]

Best regards,
Fendor

[1]: https://github.com/haskell/cabal/issues/7489
[2]: https://github.com/haskell/cabal/pull/7498