upgrade to Node v18 as minimum supported version

[thescientist13]

Type of Change

• New Feature Request
• Documentation / Website
• Improvement / Suggestion
• Bug
• Other (please clarify below)

Summary

Looking at the current NodeJS LTS Schedule, NodeJS v18.x will go into active LTS, which will be great for a number of features that would be valuable to this project.

Details

1. Native fetch
2. JSON Modules - cross-reference w/ import attributes for standard module formats; CSS and JSON  #923
3. Updated --experimental-loaders API
4. Consolidate on fetch / HTTP implementation in the project as currently we are mixing usage of request (for tests) and node-fetch (userland) and as part of this upgrade, we should consolidate on usage of (native) fetch exclusively.

This could possibly deprecate the JSON import plugin, depending on current browser support for JSON import assertions?