Change Flutter version to 8.6.0 as required version (#695)

* Change Flutter version to 8.6.0 as required version

* Fix required React Native version for customer center

Author: nyeu

src/components/CustomerCenter/CustomerCenterSDKTable.tsx

@@ -3,8 +3,8 @@ import React from "react";
 export const sdkVersions = {
   ios: "5.14.0",
   android: "8.12.2",
-  reactNative: "8.6.0",
-  flutter: "8.7.0",
+  reactNative: "8.7.0",
+  flutter: "8.6.0",
   kmp: "1.7.0",
 };