Update build.gradle

android/build.gradle

 def DEFAULT_COMPILE_SDK_VERSION = 27
 def DEFAULT_BUILD_TOOLS_VERSION = "28.0.3"
 def DEFAULT_TARGET_SDK_VERSION = 27
+def DEFAULT_SUPPORT_LIB_VERSION = "27.0.2"
 
 android {
     compileSdkVersion rootProject.hasProperty('compileSdkVersion') ? rootProject.compileSdkVersion : DEFAULT_COMPILE_SDK_VERSION
     }
 }
 
+def supportVersion = rootProject.hasProperty('supportLibVersion') ? rootProject.supportLibVersion : DEFAULT_SUPPORT_LIB_VERSION
+
 dependencies {
     implementation 'com.facebook.react:react-native:+'
+    implementation "com.android.support:appcompat-v7:$supportVersion"
     implementation "org.jetbrains.kotlin:kotlin-stdlib:$kotlin_version"
 }