Fix "Use of undeclared identifier 'ShareableValue'"

[whalemare]

Like #37 but contains single changes that allow to build ios project

[fencer-yd]

I see that this commit has not been merged into master, can I use patch to temporarily solve this problem?

`
diff --git a/node_modules/react-native-multithreading/cpp/RNMultithreadingInstaller.cpp b/node_modules/react-native-multithreading/cpp/RNMultithreadingInstaller.cpp
index 7a3e6e5..345dcbb 100644
--- a/node_modules/react-native-multithreading/cpp/RNMultithreadingInstaller.cpp
+++ b/node_modules/react-native-multithreading/cpp/RNMultithreadingInstaller.cpp
@@ -5,8 +5,8 @@

#if __has_include(<RNReanimated/Scheduler.h>)
#include <RNReanimated/Scheduler.h>
-#include <RNReanimated/ShareableValue.h>
#include <RNReanimated/RuntimeManager.h>
+#include <RNReanimated/ShareableValue.h>
#include <RNReanimated/RuntimeDecorator.h>
#include <RNReanimated/ErrorHandler.h>
#else
`

[fitouch]

@mrousavy please merge this. I have the same issue with React Native v0.68