Use a test matrix in the CI file.

Description

Switch to using a test matrix instead of separate build jobs. Also switch to using the setup-node action, which allows for pulling specific major/minor/patch versions of node.

Motivation and Context

Simplifies the CI configuration and allows for specific versions of node to run the pipeline.

Usage examples

N/A

How Has This Been Tested?

If the CI checks all pass (and there are 4 of them - node 18/20 + ubuntu/windows).

Types of changes

N/A

• 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:

• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have added tests to cover my changes.
• [ x ] All new and existing tests passed.