Fix decoding of WorkspaceState

Author: mattt

Sources/Workspace/WorkspaceState.swift

@@ -230,7 +230,7 @@ fileprivate struct WorkspaceStateStorage {
                         let path = try container.decode(AbsolutePath?.self, forKey: .path)
                         return self.init(underlying: .edited(basedOn: basedOn.map { .init($0) }, unmanagedPath: path))
                     case "downloaded":
-                        let version = try container.decode(TSCUtility.Version.self, forKey: .path)
+                        let version = try container.decode(TSCUtility.Version.self, forKey: .version)
                         return self.init(underlying: .downloaded(version: version))
                     default:
                         throw InternalError("unknown checkout state \(kind)")