Upgrade the run-qit-extension action to use Node.js v20

[eason9487]

Changes proposed in this Pull Request:

Part of #108

This PR upgrades the run-qit-extension action to use Node.js v20.

📌 Checklist before merging (@eason9487)

• Revert f0b21e0 before merging this PR

Detailed test instructions:

1. View a previous workflow run used v1 action
   • https://github.com/woocommerce/grow/actions/runs/8828789841
   • Some jobs failed due to accessing private repos with GitHub Actions bot token
   • There are warnings of using Node.js 16
     
2. View a test workflow run used updated action
   • https://github.com/woocommerce/grow/actions/runs/8829374140
   • There's no more warning of using Node.js 16
     

[mikkamp]

Thanks for these updates they look good to me.

I can confirm the warnings are no longer there in the latest run. There are a lot of temporary changes in this PR, however they look pretty sane to me.