swift build -> no such module 'PackageDescription'
swift version:
Apple Swift version 3.0-dev (LLVM b010debd0e, Clang 3e4d01d89b, Swift 7182c58cb2) Target: x86_64-apple-macosx10.9
swift package manager version:
Apple Swift Package Manager 0.1
求助,这要怎么解决……