add commonjs module file

[warrendodsworth]

Hi, I've just added a file to make it work on npm, if you could push this to https://www.npmjs.com/package/angular-toasty that'd be great, thanks.

Also great work with the plugin, really neat and simple.

[CLAassistant]

Thank you for your submission! We really appreciate it. Like many open source projects, we ask that you all sign our Contributor License Agreement before we can accept your contribution.
1 out of 2 committers have signed the CLA.

✅ Ehesp
❌ warrendodsworth
_{You have signed the CLA already but the status is still pending? Let us recheck it.}