Add support for es2015 entry point field in rollup

[gregmagolan]

Update to a version of rollup-plugin-node-resolve that supports es2015 entry points with fallback to module and main: https://github.com/gregmagolan/rollup-plugin-node-resolve/commit/7a33dc249b69497aff3380a37a359158167b4801.

Will put a PR up for rollup-plugin-node-resolve to land this in their repo.

Needed when rolling up rxjs here: angular/angular#27220

[gregmagolan]

/cc @alexeagle

[mgechev]

@gregmagolan @alexeagle is out of office for the next a couple of days. I can review the PR. I'll ping you on Slack to get a better context.

[alexeagle]

Since you have WIP on here, I assume you don't want to merge this until you get a PR merged to the upstream? Probably a wise idea to make sure the next release of rollup-plugin-node-resolve will have what we need

[gregmagolan]

@alexeagle Yes. Will have some time tomorrow morning to make a PR to the node resolve plugin

[gregmagolan]

PR submitted to rollup-plugun-node-resolve: rollup/rollup-plugin-node-resolve#186

[gregmagolan]

Looks like this change in rollup-plugin-node-resolve was already in the works which will allow for handling es2015: rollup/rollup-plugin-node-resolve#182. Will land soon hopefully.

[gregmagolan]

rollup/rollup-plugin-node-resolve#186 has still not landed. I made a custom dist based on rollup/rollup-plugin-node-resolve#186 which has been rebased to 4.0.0. Will go with that.

After #186 lands and makes it into the next rollup release we can update to that version. Its all behind the scenes so it shouldn't break anyone.