chore(ci): Run tests on Node.js 14, 16, 18

[jnv]

Description

This updates Node.js versions in build matrix to currently supported Node.js versions: v14 (EOL April 2023), v16 and v18. v17 is not supported anymore.

This is a follow-up to #187.

Motivation and Context

We should be able to guarantee compatibility with currently supported Node.js versions.

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:

• [x] I have updated the documentation accordingly. If you are changing code related to user secrets you need to really make sure that security documentation is correct.
• [x] I have read the CONTRIBUTING document.
• [x] I haven't repeated the code. (DRY)
• [x] I have added tests to cover my changes.
• [x] All new and existing tests passed.