Typecheck only once for all formats?

[Semesse]

Current Behavior

It seems that if --transpileOnly is not enabled, type checking will be applied to every format
https://github.com/formik/tsdx/blob/b91ab47e3a04e11f356f252240666b8d17c0afd8/src/createRollupConfig.ts#L179

Desired Behavior

Check types only once.

Suggested Solution

Disable type check for latter builds. I've seen a great boost for default configs, and I'd like to create a PR for this.

Who does this impact? Who is this for?

All typescript users will benefit from this since type check might be the bottleneck for most build processes.

Describe alternatives you've considered

Additional context