Add docs about new Android minSdkVersion (#766)

And adjust settings in build.gradle

CHANGELOG.md

@@ -6,6 +6,8 @@
 
   **Important:** In order to use the `OTPublisher.setVideoTransformers()` method (which uses the Vonage Media Library), you must add the Vonage Media Library separately from the Vonage Video React Native SDK. For details, see [Vonage Media Library integration](https://tokbox.com/developer/guides/vonage-media-processor/react-native/#vonage-media-library-integration).
 
+- [Update]: For Android, this version of the library requires a minimum Android API level of 24.
+
 - [Update]: This version adds support for reading the Certificate Authority certificates in the trust store of the host so that it can use them as valid root certificates when connecting to OpenTok services.
 
 - [Update]: This version adds support for Apple's requirement of the [signature for the SDK](https://developer.apple.com/support/third-party-SDK-requirements).

android/build.gradle

@@ -2,10 +2,10 @@ apply plugin: 'com.android.library'
 
 def _ext = rootProject.ext
 def _reactNativeVersion = _ext.has('reactNative') ? _ext.reactNative : '+'
-def _compileSdkVersion = _ext.has('compileSdkVersion') ? _ext.compileSdkVersion : 23
-def _buildToolsVersion = _ext.has('buildToolsVersion') ? _ext.buildToolsVersion : '23.0.1'
-def _minSdkVersion = _ext.has('minSdkVersion') ? _ext.minSdkVersion : 16
-def _targetSdkVersion = _ext.has('targetSdkVersion') ? _ext.targetSdkVersion : 23
+def _compileSdkVersion = _ext.has('compileSdkVersion') ? _ext.compileSdkVersion : 24
+def _buildToolsVersion = _ext.has('buildToolsVersion') ? _ext.buildToolsVersion : '24.0.3'
+def _minSdkVersion = _ext.has('minSdkVersion') ? _ext.minSdkVersion : 24
+def _targetSdkVersion = _ext.has('targetSdkVersion') ? _ext.targetSdkVersion : 24
 
 android {
     compileSdkVersion _compileSdkVersion