Merge Kousa Dogwood Workbench extension bump to `1.5.20`

[sharon-wang]

Bring in the Workbench extension version bump to 1.5.20 from: https://github.com/rstudio/vscode-server/pull/151.

[github-actions[bot]]

All contributors have signed the CLA ✍️ ✅
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[sharon-wang]

@cm421 would you mind commenting I have read the CLA Document and I hereby sign the CLA on this PR if you agree to the CLA?

[cm421]

I have read the CLA Document and I hereby sign the CLA

[sharon-wang]

Looking good on Ubuntu 24 :+1:

Posit Workbench 2024.12.0-daily+375.pro4, “Kousa Dogwood” (123323c8)