ts-util-is 2.0 breaks webpack builds

[mathieucaroff]

When upgrading to the last ts-util-is version, webpack starts emitting the following error during builds (on Debian and Windows) and the build fails:

Module not found: Error: Can't resolve './src/index' in 'C:\ox\node_modules\ts-util-is\dist'
Did you mean 'index.js'?
BREAKING CHANGE: The request './src/index' failed to resolve only because it was resolved as fully specified
(probably because the origin is strict EcmaScript Module, e. g. a module with javascript mimetype, a '*.mjs' file, or a '*.js' file where the package.json contains '"type": "module"').
The extension in the request is mandatory for it to be fully specified.
Add the extension to the request.

Expected behavior

The build should finish without error or warning.

Workaround

We'll keep using ts-util-is version 1.2.1 until the issue is resolved.