Update CHANGELOG to describe manifest API changes (#3989)
Update CHANGELOG to describe manifest API changes (#3989)

motivation: document user visible changes in change log

changes: Update CHANGELOG to include deprecation of dependency requirement enum calling convention
apple/swift-package-manager,apple/swift-package-manager,apple/swift-package-manager,abertelrud/swift-package-manager,abertelrud/swift-package-manager,abertelrud/swift-package-manager,apple/swift-package-manager,abertelrud/swift-package-manager,apple/swift-package-manager,abertelrud/swift-package-manager