[swift-build-dev] Swift 4 rebranch for swift-package-manager and swift-llbuild

[Rick Ballard]

Hello SwiftPM developers,

Today we rebranched the swift-4.0-branch for swift-package-manager and swift-llbuild from master, to pull all master changes into Swift 4. We've also turned on an automerge script to merge all further master changes into the swift-4.0-branch until July 31st, when we expect to turn this automerger off. After that date we expect that any remaining changes desired for Swift 4 will need to be cherry-picked to the swift-4.0-branch after release manager approval.

Thank you,

	- Rick