Replace rollup-plugin-uglify with rollup-plugin-terser for es6 compatibility

[dave-stevens-net]

rollup-plugin-uglify no longer supports es6 and should be replaced by rollup-plugin-terser.

When I ran my first prod build I received the following error using rollup-plugin-uglify:

[!] (plugin uglify) Error: Unexpected token: name «YourFirstClassReference», expected: punc «;»

To fix this on your project do the following:

npm i rollup-plugin-terser --save-dev
npm un rollup-plugin-uglify

Then replace the following 2 lines in your rollup.config.dist.js file.

-import { uglify } from 'rollup-plugin-uglify';
+import { terser } from 'rollup-plugin-terser';

-        uglify({
+        terser({