Update module format number.

This likely explains and fixes the macOS CI SIL deserialization failure.

Author: dan-zheng

lib/Serialization/ModuleFormat.h

@@ -55,7 +55,7 @@ const uint16_t SWIFTMODULE_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 SWIFTMODULE_VERSION_MINOR = 535; // top-level var decls
+const uint16_t SWIFTMODULE_VERSION_MINOR = 536; // SIL differentiability witnesses
 
 /// A standard hash seed used for all string hashes in a serialized module.
 ///