chore: Update Dockerfile to node:18.20.3

[pieterocp]

Follow up from #2515

Summary

Appeases security tooling since the updates to node causes some tools to moan.

Checklist

• The basics
  • I tested these changes manually in my local or dev environment
    • Ran the build locally, used it in my project and it seems to be working fine.
• Tests
  • Added or updated
  • N/A
    • As far as I am aware, there's no tests for using the projects container in an end to end fashion?
• Event Tracking
  • I added event tracking and followed the event tracking guidelines
    • (I cannot find any documentation for this so I guess N/A?)
  • N/A
• Error Reporting
  • [Z] N/A

Additional context

Add any other context about the pull request here. Remove this section if there is no additional context.