fix: update node engines to 18+, CI to test 18, 20, update eslint-config and eslint errors

[shazron]

How Has This Been Tested?

• npm test

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• I have signed the Adobe Open Source CLA.
• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.
• All new and existing tests passed.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (56ee808) 100.00% compared to head (57e2180) 100.00%.

Additional details and impacted files

@@            Coverage Diff            @@
##              main        #2   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files            3         3           
  Lines           65        68    +3     
  Branches         9        11    +2     
=========================================
+ Hits            65        68    +3     

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[shazron]

The tests are fine locally but since they open ports, we get ECONNREFUSED on the CI servers.
May need to change the hostname to localhost when on CI, or ipv6 loopback [::1]