Update dependency versions and migrate to Spago

[FranklinChen]

No description provided.

[hdgarrood]

Looks really nice, thanks for picking this up! Here's what I get when I try to run it locally, though:

found 2 vulnerabilities (1 moderate, 1 high)
  run `npm audit fix` to fix them, or `npm audit` for details
[error] Failed to read the config. Error was:
[error] There's no "spago.dhall" in your current location.

Could you please git add the files spago.dhall and packages.dhall?

[hdgarrood]

Thanks!