ci: Disable optimization in the haskell-ci workflow

Cuts a couple dozen seconds from the build. This was already disabled in
the Stack workflow and we just forgot to put it here as well.

Related: https://github.com/xmonad/xmonad-contrib/pull/580

.github/workflows/haskell-ci.yml

@@ -146,6 +146,8 @@ jobs:
           echo "package xmonad" >> cabal.project
           echo "    ghc-options: -Werror=missing-methods" >> cabal.project
           cat >> cabal.project <<EOF
+          optimization: False
+
           package xmonad
             flags: +pedantic
           EOF

cabal.haskell-ci

@@ -9,5 +9,6 @@ github-patches:
   .github/workflows/haskell-ci-hackage.patch
 
 raw-project
+  optimization: False
   package xmonad
     flags: +pedantic