No Import Assertions

Disallows the assert keyword for import attributes.

ES import attributes (previously called import assertions) has been changed to use the with keyword. The old syntax using assert is still supported, but deprecated.

Invalid:

import obj from "./obj.json" assert { type: "json" };
import("./obj2.json", { assert: { type: "json" } });

Valid:

import obj from "./obj.json" with { type: "json" };
import("./obj2.json", { with: { type: "json" } });