Use "import attributes" instead of "import assertions"

[andrewbrey]

Per the history of the TC39 spec for this feature (https://github.com/tc39/proposal-import-attributes?tab=readme-ov-file#history) the most current syntax for "import attributes" uses the with keyword instead of the assert keyword.

Usage of this module with Deno (as of Deno 1.46, ref) now causes a deprecation warning due to usage of the deprecated "import assertions" syntax in user-agent.ts:

import untypedUserAgents from './user-agents.json' assert { type: 'json' };

Since this is deprecated syntax (and also because using assert instead of with causes a warning in Deno and eventually, likely, in other runtimes) it would be great to update the one "import assertion" that uses assert { type: 'json' } to instead be an "import attribute" that uses the with keyword, e.g. with { type: 'json' }

[EHadoux]

It's not just a warning, it's a SyntaxError on node 22.

[EHadoux]

Any update on this?