readme modify to btfs need xcode 10.2

jingliancui · jingliancui · commit 80f158cc8256 · 2020-09-02T09:04:45.000+08:00
diff --git a/README.md b/README.md
@@ -14,7 +14,7 @@ The packaging of BTFS is still evolving, and we expect to provide a binding proj
 
 ## Caution ❗
 
-For contributing Binding-Tool-For-Swift, your Xcode version required 12!
+In order to contribute to Binding-Tools-For-Swift, you will need Xcode 10.2 !
 
 ## Current Status
 
