Fixed failed to parse sourcemaps error

[Taskle]

This fixes the issue surfaced in #522 that generates console warnings for anyone who imports rrule into their project.

I've tested it locally in my forked version and it appears to remove the errors.

[davidgoli]

Thanks, for the contribution! The problem with this approach is it points to the src/ folder in the production output, which ideally we shouldn't be even publishing.

What I propose we do instead is not minify the published output, then you won't even need sourcemaps. Most end-stage build tools minify the whole bundle including node_modules in application code, so I don't think this will have too much downside.

[dargmuesli]

I've create two PRs which fix the situation for now:

• fix(sourcemaps): remove #637
• fix(sourcemaps): inline sources #634

@davidgoli I'd invite you to pick the one that makes more sense. Just having sourcemaps which point to non-existing source files makes not much, I'd say 🤙