support windows build ?

[CharlesTaylor7]

The flake.nix file only supports linux, but I suspected the project would build on other platforms using cabal directly.

Here's how I got this to build:

• Get GHCup (https://www.haskell.org/ghcup/)
• Use ghcup to install the recommended cabal version
• Use ghcup to install GHC 9.2.x Clone the repo and run cabal install in the root directory. That will build and install pslua to $HOME/.cabal/bin/pslua.

Those steps worked for me on an Arm Macbook, but they ought to work on Windows too since ghcup, cabal, and ghc are cross platform.

[Unisay]

I've added instructions how to build pslua.exe on Windows to the README.md