Update Rollup to latest 3.x and update plugins

This gets rid of a security vulnerability in the dependencies. There
don't seem to be any breaking changes.

We cannot update to Rollup 4.x, as rollup-plugin-dts is blocking that;
it requires Node 16 from 6.0.1 onwards.

rollup/plugin-terser would require Node 20 from 1.0.0 onwards.

Author: ptomato