[Serialization] Update Module Format version

Author: xedin

include/swift/Serialization/ModuleFormat.h

@@ -55,7 +55,7 @@ const uint16_t VERSION_MAJOR = 0;
 /// describe what change you made. The content of this comment isn't important;
 /// it just ensures a conflict if two people change the module format.
 /// Don't worry about adhering to the 80-column limit for this line.
-const uint16_t VERSION_MINOR = 408; // Last change: begin_access [nontracking]
+const uint16_t VERSION_MINOR = 409; // Last change: standalone requirement subs
 
 using DeclIDField = BCFixed<31>;