v3.0.1 Treeshaking for `module` and `browser`

package.json module and browser is now pointing to ./src/stopword.js to make it tree shakeable. And jsdelivr is pointed to ./dist/stopword.umd.min.js to not make issues for the CDN-usage.

The stopword module has gotten bigger over the years, so making treeshaking possible will make it possible to reduse unnecessary loading of languages not used.

Non-breaking release in most cases, but a big enough change to bump it to a new major version and there might be some corner cases that breaks.