Update Installing.md (#3623)

docs/docs/Installing.md

@@ -117,7 +117,8 @@ dependencies {
 ><br><br>Available options:
 >
 >* `reactNative51`: Support for React Native 0.51-0.54
->* `reactNative55`: Support for React Native 0.55 and above
+>* `reactNative55`: Support for React Native 0.55
+>* `reactNative56`: Support for React Native 0.56 and above
 >
 ><br>For example, To target React Native 0.55, replace the following line:<br>
 >`missingDimensionStrategy "RNN.reactNativeVersion", "reactNative51"`