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 (1416fba) 100.00% compared to head (47515ae) 100.00%.

Additional details and impacted files

@@            Coverage Diff            @@
##            master       #30   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files            4         4           
  Lines          117       119    +2     
  Branches        15        17    +2     
=========================================
+ Hits           117       119    +2     

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