Update README.md

Author: amit-kremer93

README.md

@@ -13,7 +13,7 @@
 ### <a id="plugin-build-for"> This plugin is built for
 
 - Android AppsFlyer SDK **v6.13.0**
-- iOS AppsFlyer SDK **v6.13.0**
+- iOS AppsFlyer SDK **v6.13.1**
 
 ## <a id="breaking-changes"> ❗❗ Breaking changes when updating to v6.x.x❗❗