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/SPUStandardUserDriver.h

@@ -0,0 +1,44 @@
+//
+//  SPUStandardUserDriver.h
+//  Sparkle
+//
+//  Created by Mayur Pawashe on 2/14/16.
+//  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/SPUUserDriver.h>
+#import <Sparkle/SUExport.h>
+
+NS_ASSUME_NONNULL_BEGIN
+
+@protocol SPUStandardUserDriverDelegate;
+
+/**
+ Sparkle's standard built-in user driver for updater interactions
+ */
+SU_EXPORT @interface SPUStandardUserDriver : NSObject <SPUUserDriver>
+
+/**
+ Initializes a Sparkle's standard user driver for user update interactions
+ 
+ @param hostBundle The target bundle of the host that is being updated.
+ @param delegate The optional delegate to this user driver.
+ */
+- (instancetype)initWithHostBundle:(NSBundle *)hostBundle delegate:(nullable id<SPUStandardUserDriverDelegate>)delegate;
+
+/**
+ Use initWithHostBundle:delegate: instead.
+ */
+- (instancetype)init NS_UNAVAILABLE;
+
+@end
+
+NS_ASSUME_NONNULL_END