Introduce ICUExport: a command utility that upgrades the ICU version for the swift-foundation-icu, based on ICU releases from apple-oss-distribution

[iCharlesHu]

ICUExport is a command utility that is used to upgrade swift-foundation-icu's ICU version to match the version released by apple-oss-distribution. The goal for these upgrades is to ensure SwiftFoundation uses the same ICU version on all platforms.

[iCharlesHu]

@swift-ci please test

[itingliu]

I can't tell what's wrong with the format check. Are you able to tell?

[iCharlesHu]

@itingliu I think I used the wrong header in one of the files. Should be fixed now.

[iCharlesHu]

@swift-ci please test

[itingliu]

The format check is still failing and I'm still not able to find any useful logs besides Error: Process completed with exit code 1.

It looks like it's running this script for format-check:
https://github.com/swiftlang/github-workflows/blob/main/.github/workflows/scripts/check-swift-format.sh

so I tried running this script manually. I'm seeing all of the diffs it outputs to replace 4-whitespace indentation into 2-whitespace ones, but I'm not hitting any exit code 1. I'm not sure if I misunderstood how the script is supposed to test and work though. Do you know if this soundness check is supposed to fail if we don't use the predefined 2-space format?