[js] Incorporate renovate

[Jordan-Mysten]

We should incorporate renovate to manage automatically updating dependencies. Normally we would leverage dependabot but it doesn't support pnpm, so renovate is a good choice for us.

• Do we want to manage all dependencies (including cargo) with renovate?
• Do we want to auto-merge?
• What do we want the configuration to be for pnpm?

https://github.com/renovatebot/renovate