Bumped RN version in docs (#1404)

Author: alexandergoncharov-zz

README.md

@@ -69,7 +69,7 @@ We try our best to maintain backwards compatibility of our plugin with previous
 | v0.46                   | v4.0+ *(RN refactored js bundle loader code)*         |
 | v0.46-v0.53             | v5.1+ *(RN removed unused registration of JS modules)*|
 | v0.54-v0.55             | v5.3+ *(Android Gradle Plugin 3.x integration)*       |
-| v0.56                   | v5.4+ *(RN upgraded versions for Android tools)*      |
+| v0.56-v0.57             | v5.4+ *(RN upgraded versions for Android tools)*      |
 
 We work hard to respond to new RN releases, but they do occasionally break us. We will update this chart with each RN release, so that users can check to see what our "official" support is.