[SwiftShims] Include Target.h in the modulemap for SwiftShims

Author: kubamracek

stdlib/public/SwiftShims/swift/shims/module.modulemap

@@ -18,6 +18,7 @@ module SwiftShims {
   header "SwiftStddef.h"
   header "SwiftStdint.h"
   header "System.h"
+  header "Target.h"
   header "ThreadLocalStorage.h"
   header "UnicodeData.h"
   header "Visibility.h"