fix. doc

README.md

 The react-native-agora is an open-source wrapper for react-native developers. This SDK takes advantage of React Native and Agora RTC Video SDKs on Android/iOS.
 
 ## Compatibility
-  * react native 0.58.x
+  * >= react native 0.55.x
   * iOS SDK 8.0+
   * Android 5.0+ x86 arm64 armv7a
 

docs/api/index.html

 				<p>The react-native-agora is an open-source wrapper for react-native developers. This SDK takes advantage of React Native and Agora RTC Video SDKs on Android/iOS.</p>
 				<h2 id="compatibility">Compatibility</h2>
 				<ul>
-					<li>react native 0.58.x</li>
+					<li>react native 0.55.x</li>
 					<li>iOS SDK 8.0+</li>
 					<li>Android 5.0+ x86 arm64 armv7a</li>
 				</ul>

docs/v2/ios.md

 # React native Agora iOS Installation
 #### Minimum compatibility
-* React native 0.58.x
+* >= React native 0.55.x
 * iOS SDK 8.0+
 * Android 5.0+ x86 arm64 armv7a
 

docs/v2/ios.zh.md

 # iOS 开发搭建指南
 #### 最低兼容
-* React Native 0.58.x
+* >= React Native 0.55.x
 * iOS SDK 8.0+
 * Android 5.0+ x86 arm64 armv7a