Enable the base localization because Xcode insists

Author: mdiep

ReactiveSwift.xcodeproj/project.pbxproj

@@ -805,6 +805,7 @@
 			hasScannedForEncodings = 0;
 			knownRegions = (
 				en,
+				Base,
 			);
 			mainGroup = D04725E019E49ED7006002AA;
 			productRefGroup = D04725EB19E49ED7006002AA /* Products */;