Branch cut for 5.9 release

[Yuta Saito]

TODO

• Cut swiftwasm-release/5.9 branch from XXX, where is the most recent upstream-merge before release/5.9 branch cut. And merge release/5.9 changes into the branch. e95edff
  • git branch swiftwasm-release/5.9 XXX
  • git checkout swiftwasm-release/5.9
  • git fetch apple release/5.9
  • git merge apple/release/5.9
• Update update-checkout-config.json
• Update TOOLCHAIN_CHANNEL with 5.9 in .github/workflows/build-toolchain.yml
• Cut corelibs release branches
  • https://github.com/swiftwasm/swift-corelibs-foundation
  • https://github.com/swiftwasm/swift-corelibs-xctest
• Fix CI docker image revision by docker pull ghcr.io/swiftwasm/swift-ci:main-ubuntu-18.04@sha256: e5f653f13176c6c3aee5b3b864001f6ccba06584881ea0343b3822b98b084a06 style

References

• Previous branch cut: #5122

[Geordie J]

Just wondering if https://github.com/apple/swift-foundation might get a look for the 5.9 release (see here for more info).

The fact that it splits out the ICU dependencies into a separate module could mean use cases like JSONDecoder/Encoder, NSAttributedString, etc. could be made available to devs without sacrificing binary size. That could address issues like #4171.

It should be possible to build swift-foundation manually with the 5.9 branch, but that might lead to conflicts if swift-corelibs-foundation is bundled with the toolchain. I'm not sure.

[Yuta Saito]

The brand-new foundation is still not completely compatible with the existing corelibs-foundation, so I don't have any plan to bundle it in the toolchain for now.

[Yuta Saito]

Added 5.9 release scheme in https://github.com/swiftwasm/swiftwasm-build/tree/main/schemes/release-5.9 and nightly toolchain is now shipped every night