Add South Sudan (Juba) to Windows time zone mapping

[daniel-ju]

Summary

This updates the windowsZones.txt data file after cherry-picking the upstream CLDR changes to windowsZones.xml from here:

Upstream PR: unicode-org/cldr#1193
CLDR ticket: https://unicode-org.atlassian.net/browse/CLDR-14653

PR Checklist

• I have verified that my change is specific to this fork and cannot be made upstream.
• I am making a maintenance related change.
• I am making a change that is related to usage internal to Microsoft.
• I am making a change that is related to the Windows OS build of ICU.
• CLA signed. If not, please see here to sign the CLA.

[jefgen]

Thanks for updating this!

FYI: This will resolve #90 once checked-in. :)