[Feature]: support dynamic import by default

[hardfist]

when I use tsm register to transpile module which contains dynamic import, it's broken

• src/index.ts

  async function main(){
  const mod = await import('./lib');
  }
  main();

• src/lib.ts

  export const answer = 42;

  It's broken

It's because esbuild will keep dynamic import for high version of node, even you set format=cjs https://github.com/evanw/esbuild/issues/1636

when I set target to node12, it works fine now, because it will transform dynamic import to require

• tsm.js

  module.exports = {
  common: {
  target: 'node12'
  }
  }

  so I think we could set target=node12 by default to support dynamic import by default

[lukeed]

What versions of Node and esbuild are you using? The support range for import() was fixed here: https://github.com/evanw/esbuild/issues/1772

It's not wise to make node12 the target for all runtimes, because it's untrue for non-12.x runtimes.

[hardfist]

I'm using node@16.8.0