Add support for Apple Silicon

-Update classes to read correct Apple Silicon CPU sensor
-Update project to compile a Universal 2 binary. Upgraded Sparkle to 2.1.0 as that was the latest and supports ARM64.
-Add MacBookPro18,1 to Machines.plist

Sparkle.framework/Versions/B/Headers/SUUpdatePermissionResponse.h

@@ -0,0 +1,47 @@
+//
+//  SUUpdatePermissionResponse.h
+//  Sparkle
+//
+//  Created by Mayur Pawashe on 2/8/16.
+//  Copyright © 2016 Sparkle Project. All rights reserved.
+//
+
+#if __has_feature(modules)
+#if __has_warning("-Watimport-in-framework-header")
+#pragma clang diagnostic ignored "-Watimport-in-framework-header"
+#endif
+@import Foundation;
+#else
+#import <Foundation/Foundation.h>
+#endif
+#import <Sparkle/SUExport.h>
+
+/**
+ This class represents a response for permission to check updates.
+*/
+SU_EXPORT @interface SUUpdatePermissionResponse : NSObject<NSSecureCoding>
+
+/**
+ Initializes a new update permission response instance.
+ 
+ @param automaticUpdateChecks Flag for whether to allow automatic update checks.
+ @param sendSystemProfile Flag for if system profile information should be sent to the server hosting the appcast.
+ */
+- (instancetype)initWithAutomaticUpdateChecks:(BOOL)automaticUpdateChecks sendSystemProfile:(BOOL)sendSystemProfile;
+
+/*
+ Use -initWithAutomaticUpdateChecks:sendSystemProfile: instead.
+ */
+- (instancetype)init NS_UNAVAILABLE;
+
+/**
+ A read-only property indicating whether automatic update checks are allowed or not.
+ */
+@property (nonatomic, readonly) BOOL automaticUpdateChecks;
+
+/**
+ A read-only property indicating if system profile should be sent or not.
+ */
+@property (nonatomic, readonly) BOOL sendSystemProfile;
+
+@end