build: support ES modules

[oblador]

Description

This package can't be used in a node environment using ESM as it's neither declared as "type": "module" nor does it include .mjs extensions for the files in the module main field.

Since TSC is not able to produce proper ESM files with .mjs extensions I opted to use tsup to compile the ESM files, and I also had to add @swc/core to keep this backwards compatible with the es5 target. I don't think there's much point in supporting back to es5 for an ESM, but I'm keeping it for now to avoid making this a breaking change.

Fixes #2353

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as before)

Checklist

• Read the Contributing Guide
• Perform a code self-review
• Comment the code, particularly in hard-to-understand areas
• Add documentation
• Add hook's story at Storybook
• Cover changes with tests
• Ensure the test suite passes (yarn test)
• Provide 100% tests coverage
• Make sure code lints (yarn lint). Fix it with yarn lint:fix in case of failure.
• Make sure types are fine (yarn lint:types).