Even if we put #73 in place, we could tag or create release branches so that downstream "uses" of swift_package_test.yml specify a constant semvar version instead of always working off of main which is more susceptible to breaking.

For example: swiftlang/github-workflows/.github/workflows/[email protected]

Looks possible to automate with certain marketplace actions like https://github.com/marketplace/actions/tag-release-on-push-action, but manually bumping as need may be sufficient