Update module build output to improve compatibility for ESM modules

[DJDANNY123]

Updates the tsup build configuration to package ESM module code with the .mjs file format, which ensures that CommonJs index.js is packaged into the same directory as index.mjs, and the types can be resolved from both.

[vscheuber]

@DJDANNY123 thank you for your PR! Can you tell me a bit more about the issues you are encountering without the change?

[DJDANNY123]

Due to the nature of legacy modules being enabled in tsup, the types are not specified correctly for consumers using ESM modules. When we attempt to consume frodo with the tsconfig of NodeNext for module and moduleResolution, or ESNext for module and Bundler for moduleResolution, it is unable to determine types.

`
Could not find a declaration file for module '@rockcarver/frodo-lib'. '.../node_modules/.pnpm/@rockcarver+frodo-lib@2.0.3/node_modules/@rockcarver/frodo-lib/dist/esm/index.js' implicitly has an 'any' type.

There are types at '.../node_modules/@rockcarver/frodo-lib/dist/index.d.ts', but this result could not be resolved when respecting package.json "exports". The '@rockcarver/frodo-lib' library may need to update its package.json or typings.ts(7016)
`

[vscheuber]

Fantastic, thanks @DJDANNY123 . Let me run the tests and make sure frodo-cli digests the change well and I'll merge the PR. I do have a crammed week ahead so it might take me a few days to get through everything.

[DJDANNY123]

Hi @vscheuber do you think you'll be able to have a look at this one today or is it looking like next week?

[vscheuber]

@DJDANNY123 I did merge your PR a few mins ago. I will probably trigger a patch release now as well, so you can pull it from an official version vs a pre-release but your PR is in 2.1.1-0 for now.

[vscheuber]

@DJDANNY123 alright, it's in 2.1.1 now. Thank you for the contribution!