Missing `prepare` script preventing usage of unreleased version directly from the Github repo.

[manojVivek]

Hi, recently we has this fix merged to this repo that we ran into in our application. Since there is no release cut after that merge (btw, appreciate a new release now), we wanted to use the unpublished version via pnpm's Github package installation using
pnpm add github:uwdata/flechette#bbeb29d

But this is not really helpful as the package is missing a prepare script that is needed to build the package after pulling from the Github repo.

[manojVivek]

@jheer I tried adding it in #72, but the built package after pnpm install is still missing some type definition files.

Wondering if you do any additional type compilation steps in your release workflow? 🤔

[jheer]

There is the postbuild script: "postbuild": "npm run types", but otherwise that's it.

[manojVivek]

Ok great, I just tried it again and the prepare command addition in #72 just works fine for my local installation.

Probably the recent changes to tsconfig.json fixed it and I was trying with a version before that.