Update target sdk version

libcodec2-android/build.gradle

@@ -12,7 +12,7 @@ buildscript {
 }
 
 android {
-    compileSdkVersion 28
+    compileSdkVersion 30
 
     compileOptions {
         sourceCompatibility JavaVersion.VERSION_1_8
@@ -21,7 +21,7 @@ android {
 
     defaultConfig {
         minSdkVersion 16
-        targetSdkVersion 28
+        targetSdkVersion 30
         versionCode 1
         versionName "1.0"
         testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"