Add npm dist-tag @next for testing the Version 2

[jmorille]

Add to npm reposiotry the dist-tag next in order to test theVersion 2.0.0 of your exporter

Like polymer-cli,

# npm view  polymer-cli dist-tags
{ latest: '1.5.4', apache: '0.7.1-apache', next: '0.18.1' }

It explain in the stackoverflow below

• https://stackoverflow.com/questions/40621566/what-package-version-does-next-specify-for-npm or the npm documentation https://docs.npmjs.com/cli/dist-tag

npm dist-tag add <pkg>@<version> [<tag>]
npm dist-tag rm <pkg> <tag>
npm dist-tag ls [<pkg>]

aliases: dist-tags