Update to node20 and use package instead of node_modules & bugfixes

[humble-barnacle001]

Hi,
I wanted to improve certain things and make some bugfixes:

• use a package instead of node_modules folder as per GitHub recommendations
• upgrade to node 20 runner from node 16 to resolve actions warning
• fix a typo in variable in index.js
• use .env file instead of modifying test_config

[joshcai]

Thank you @humble-barnacle001 - these improvements are great! I didn't know the recommendation to commit the node_modules has changed, I'm glad we no longer have to do that.

[joshcai]

I believe if process.env.VERBOSE === false, this would still turn into true with ||, I think ?? would work better for all of these. I'll change it on my side since I'm about to update the code a bit and don't want you to have to deal with the merge conflicts.