[Feature] Support updating JSR.io dependencies

[jahands]

Description

JSR is a package registry created by the Deno team. JSR dependencies can be installed in non-Deno projects using other package managers using their jsr utility.

Here's an example:

pnpm jsr i @std/fmt@latest

This results in a dependency in package.json that looks like this:

"npm:@jsr/[email protected]",

From this point, pnpm (or any other node-style package manager) is able to install it normally as far as I can tell.

The only problem is that syncpack can't check for updates for these dependencies when using syncpack update.

Suggested Solution

From our thread on Twitter, it sounds like this is something Syncpack could support: https://docs.deno.com/runtime/fundamentals/standard_library/#versioning-and-stability

Help Needed

I would love to contribute this feature, but don't have the time unfortunatley. JSR support would be great because the Deno team manages a nice "Standard Library" on JSR. Thanks!