enhancement/issue 1202 bump to minimum NodeJS 20.x version of 20.18.3

[thescientist13]

Related Issue

#1202

Documentation

N / A

Summary of Changes

1. Node 20.18.3 was released which marks JSON Import Attributes as stable (we use JSON modules in walker-package-ranger.js)

   [030f155986] - esm: mark import attributes and JSON module as stable (Nicolò Ribaudo) #55333

2. Bump minimum Node version in .nvmrc and netlify.toml
3. Fix Node versions badge link in README.md

Note: this overlaps with actions/runner-images#1401 , but made it its own PR since it touches a different version range, and is also a breaking change

TODO

1. Looks like we need to wait for GitHub Actions to catch up?
   • maybe need to add check-latest? - Security: lts/* installs old LTS versions up to 9 days after release actions/setup-node#1236

   error @greenwood/cli@0.31.0: The engine "node" is incompatible with this module. Expected version "^18.20.5 || ^20.18.3 || ^22.12.0". Got "20.18.2"
   error Found incompatible module.