Update to Deno 2.0

[thoroc]

Just looking at this and it seems the templates' code are producing pre deno 2.0 code.

For example:

• packages/deno/src/generators/application/files/framework-none/main.ts__template__

import { handler } from './handler.ts';

const port = Number(Deno.env.get('PORT') || 4200);

Deno.serve({ port }, handler); // <-- this has changed

• packages/deno/src/generators/application/files/framework-none/handler.test.ts__template__

import { assertInstanceOf } from 'jsr:@std/assert'; // <-- this has changed
import { handler } from './handler.ts';

Deno.test('handler', async () => {
  const response = await handler(new Request('http://localhost:3000'));
  assertInstanceOf(
    response,
    Response,
    'handler did not return an instance of a Response'
  );
});

I am sure there are plenty of other places updates are needed, including the deno.json file itself (I don't think importMap are a thing anymore btw).