Update samples for Android R ( api level 30 )

Author: ggfan

People/app/build.gradle

@@ -2,11 +2,12 @@ apply plugin: 'com.android.application'
 apply plugin: 'kotlin-android'
 
 android {
-    compileSdkVersion 'android-R'
+    compileSdkVersion 30
+
     defaultConfig {
         applicationId 'com.example.android.people'
-        minSdkVersion 'R'
-        targetSdkVersion 'R'
+        minSdkVersion 30
+        targetSdkVersion 30
         versionCode 1
         versionName '1.0'
         testInstrumentationRunner 'androidx.test.runner.AndroidJUnitRunner'

WindowInsetsAnimation/app/build.gradle

@@ -18,12 +18,12 @@ apply plugin: 'com.android.application'
 apply plugin: 'kotlin-android'
 
 android {
-    compileSdkVersion "android-R"
+    compileSdkVersion 30
 
     defaultConfig {
         applicationId "com.google.android.samples.insetschat"
-        minSdkVersion "R"
-        targetSdkVersion "R"
+        minSdkVersion 30
+        targetSdkVersion 30
         versionCode 1
         versionName "1.0"
     }