Update OGChangedValueFlags (#118)

Author: Kyle-Ye

Sources/OpenGraph_SPI/Attribute/OGChangedValueFlags.h

@@ -11,8 +11,8 @@
 #include "OGBase.h"
 
 typedef OG_OPTIONS(uint32_t, OGChangedValueFlags) {
-    OGChangedValueFlags_0 = 0,
     OGChangedValueFlags_1 = 1 << 0,
+    OGChangedValueFlagsRequiresMainThread = 1 << 1,
 };
 
 #endif /* OGChangedValueFlags_h */