fix: omit dynamic from property attributes

[t0rr3sp3dr0]

@dynamic is only meant to be used inside an @implementation block, it should never appear inside @interface and @protocol blocks. This patch prevents go-macho from generating a header with that attribute.

Before:

@interface AXAuditTimedResult : NSObject

@property (retain, nonatomic) NSDate *startTime;
@property (retain, nonatomic) NSDate *endTime;
@property (readonly, @dynamic, nonatomic) NSString *executionTimeString;

@end

After:

@interface AXAuditTimedResult : NSObject

@property (retain, nonatomic) NSDate *startTime;
@property (retain, nonatomic) NSDate *endTime;
@property (readonly, nonatomic) NSString *executionTimeString;

@end

[t0rr3sp3dr0]

PTAL