`deno init` should have `@std/assert` as bare specifier

[dsherret]

import { assertEquals } from "jsr:@std/assert";
import { add } from "./mod.ts";

Deno.test(function addTest() {
  assertEquals(add(2, 3), 5);
});

Would be better to be:

import { assertEquals } from "@std/assert";
import { add } from "./mod.ts";

Deno.test(function addTest() {
  assertEquals(add(2, 3), 5);
});

Using a proper version constraint in the deno.json. If the version can't be determined then it should fallback to @1