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/SPUUpdatePermissionRequest.h

@@ -0,0 +1,40 @@
+//
+//  SPUUpdatePermissionRequest.h
+//  Sparkle
+//
+//  Created by Mayur Pawashe on 8/14/16.
+//  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/SUExport.h>
+
+NS_ASSUME_NONNULL_BEGIN
+
+/**
+ This class represents information needed to make a permission request for checking updates.
+ */
+SU_EXPORT @interface SPUUpdatePermissionRequest : NSObject<NSSecureCoding>
+
+/**
+ Initializes a new update permission request instance.
+ 
+ @param systemProfile The system profile information.
+ */
+- (instancetype)initWithSystemProfile:(NSArray<NSDictionary<NSString *, NSString *> *> *)systemProfile;
+
+/**
+ A read-only property for the user's system profile.
+ */
+@property (nonatomic, readonly) NSArray<NSDictionary<NSString *, NSString *> *> *systemProfile;
+
+@end
+
+NS_ASSUME_NONNULL_END