Add `pkg.pr.new` support

[gameroman]

Describe the feature

For example if there's a pkg.pr.new release like https://pkg.pr.new/knip@1853, npmx would allow seeing it's information via https://npmx.dev/pkg.pr.new/knip@1853

Additional information

• Would you be willing to help implement this feature?

Final checks

• Read the contribution guide.
• Check existing issues.