Support the vite build system

[mjarkk]

Wanted to add this plugin to a vite project but got this error:
Note vite outputs javascript modules by default (this should also be possible directly in rollup but as vite uses that under the hood but this is an easier example)

[prepack] Syntax error: 'import' and 'export' may appear only with 'sourceType: "module"' (1:0)

How to copy: Setup a fresh vite project and add this plugin and try to build the project

Env: Package version: 1.1.1