haskell-gi: Include haskell-gi-overloading 0.0

Using this version turns off overloading in all the haskell-gi packages.
See haskell-gi/haskell-gi#107 for details.

pkgs/development/haskell-modules/configuration-hackage2nix.yaml

@@ -2533,6 +2533,7 @@ extra-packages:
   - haddock-api == 2.15.*               # required on GHC 7.8.x
   - haddock-api == 2.16.*               # required on GHC 7.10.x
   - haddock-library == 1.2.*            # required for haddock-api-2.16.x
+  - haskell-gi-overloading == 0.0       # required for using haskell-gi packages without overloading
   - haskell-src-exts == 1.18.*          # required by hoogle-5.0.4
   - mtl < 2.2                           # newer versions require transformers > 0.4.x, which we cannot provide in GHC 7.8.x
   - mtl-prelude < 2                     # required for to build postgrest on mtl 2.1.x platforms