Remove module.exports

That uhh, that was a stupid tired mistake. Does not do what I want it to do because I want it to work with `import` properly to make it easier to import, and importing with require is still as easy as `const { DMManager } = require('yamdbf-dm-manager');`

src/index.ts

@@ -1,4 +1,3 @@
 import { DMManager } from './DMManager';
 export { DMManager };
 export default DMManager;
-module.exports = DMManager;