Fix erroneously re-throwing reduce (on Swift 5.3 pre-release) within …

…global (via static nature) variable initializer.

Error looked like:

```
/Users/crusty/Projects/Xcode/Carthage/Source/XCDBLD/SDK.swift:80:3: error: call can throw, but errors cannot be thrown out of a global variable initializer
                KeyValuePairs.reduce([
                ^
```

Co-authored-by: J.D. Healy <[email protected]>

Source/XCDBLD/SDK.swift

@@ -77,15 +77,15 @@ public struct SDK: Hashable {
 	///            hardcoded `simulatorHeuristic` · all keyed by lowercased `name`.
 	/// - Note: The aliases are intended to be matched case-insensitevly.
 	private static let knownIn2019YearDictionary: [String: (String, [String], String)] =
-		KeyValuePairs.reduce([
+		([
 			"MacOSX": (["macOS", "Mac", "OSX"], "macOS"),
 			"iPhoneOS": (["iOS Device", "iOS"], "iOS"),
 			"iPhoneSimulator": (["iOS Simulator"], "Simulator - iOS"),
 			"WatchOS": (["watchOS"], "watchOS"),
 			"WatchSimulator": (["watchOS Simulator", "watchsimulator"], "Simulator - watchOS"),
 			"AppleTVOS": (["tvOS"], "tvOS"),
 			"AppleTVSimulator": (["tvOS Simulator", "appletvsimulator", "tvsimulator"], "Simulator - tvOS"),
-		])(into: [:]) {
+		] as KeyValuePair).reduce(into: [:]) {
 			$0[$1.0.lowercased()] = ($1.0, $1.1.0, $1.1.1)
 		}