Can't publish/build on Windows (easily)

[turt2live]

It's difficult to set this project up on Windows, and npm interactions (particularly after #31 lands for publishing) are near-impossible.

The major points of concern are:

• ../schemas/*.json doesn't expand on Windows, so the OS tries to open a literal ../schemas/*.json file (which doesn't exist). This prevents npm build from working.
• The npm scripts launch bash windows which might not expose a proper exit code when they fail, which won't necessarily fail the commands.
  • The scripts are also shell scripts, which causes issues in general for non-bash-enabled hosts.
  • A possible fix for this is to use the low-risk parts of shelljs: https://github.com/matrix-org/matrix-rust-sdk-bindings/blob/72b8b7ef7b5bef72f4d88dc45a92088b3f3a6700/crates/matrix-sdk-crypto-nodejs/check-exists.js#L7

Workaround steps for publishing (post-#31) are:

1. Use WSL
2. yarn install
3. yarn build:ts (run the prepublish script manually)
4. Go back to the host
5. Disable prepublishOnly by renaming it
6. npm publish --access public

It's obviously not great to have to jump around between VMs to do a release though.