feat: Upgrade to Node.js v20

[jeremylorino]

Motivation and Context

Modernize the action and the npm dependencies. GitHub deprecated set-output command which is properly deprecated in the latest of @action/core.

More info can be found in the upstream issue.

Description

• Upgraded to Node.js v20
• Upgraded dependencies
  • @actions/core
    • Fixes https://github.com/dorshinar/get-deployment-url/issues/24
  • @actions/github
  • eslint
• Switch from @zeit/ncc to @vercel/ncc
  • Pulled from GitHub Actions Javascript template

Before

After

[dorshinar]

Thanks for taking the time to do it!