[shared_preferences] Update gradle/agp in example apps (#3809)

partial take over from https://github.com/flutter/packages/pull/3742
Tools 8.0 is not supported yet see https://github.com/flutter/flutter/issues/125181
https://github.com/flutter/flutter/issues/122213
diff --git a/packages/shared_preferences/shared_preferences/example/android/build.gradle b/packages/shared_preferences/shared_preferences/example/android/build.gradle
index 21d5069..4b30292 100644
--- a/packages/shared_preferences/shared_preferences/example/android/build.gradle
+++ b/packages/shared_preferences/shared_preferences/example/android/build.gradle
@@ -1,12 +1,12 @@
 buildscript {
-    ext.kotlin_version = '1.3.50'
+    ext.kotlin_version = '1.6.21'
     repositories {
         google()
         mavenCentral()
     }
 
     dependencies {
-        classpath 'com.android.tools.build:gradle:7.0.1'
+        classpath 'com.android.tools.build:gradle:7.4.2'
         classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
     }
 }
@@ -26,6 +26,6 @@
     project.evaluationDependsOn(':app')
 }
 
-task clean(type: Delete) {
+tasks.register("clean", Delete) {
     delete rootProject.buildDir
 }
diff --git a/packages/shared_preferences/shared_preferences/example/android/gradle/wrapper/gradle-wrapper.properties b/packages/shared_preferences/shared_preferences/example/android/gradle/wrapper/gradle-wrapper.properties
index b8793d3..cfe88f6 100644
--- a/packages/shared_preferences/shared_preferences/example/android/gradle/wrapper/gradle-wrapper.properties
+++ b/packages/shared_preferences/shared_preferences/example/android/gradle/wrapper/gradle-wrapper.properties
@@ -3,4 +3,4 @@
 distributionPath=wrapper/dists
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-7.0.2-all.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-7.6.1-all.zip
diff --git a/packages/shared_preferences/shared_preferences_android/example/android/build.gradle b/packages/shared_preferences/shared_preferences_android/example/android/build.gradle
index 23a5996..c11ef06 100644
--- a/packages/shared_preferences/shared_preferences_android/example/android/build.gradle
+++ b/packages/shared_preferences/shared_preferences_android/example/android/build.gradle
@@ -1,12 +1,12 @@
 buildscript {
-    ext.kotlin_version = '1.3.50'
+    ext.kotlin_version = '1.6.21'
     repositories {
         google()
         mavenCentral()
     }
 
     dependencies {
-        classpath 'com.android.tools.build:gradle:7.0.1'
+        classpath 'com.android.tools.build:gradle:7.4.2'
         classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
     }
 }
@@ -26,7 +26,7 @@
     project.evaluationDependsOn(':app')
 }
 
-task clean(type: Delete) {
+tasks.register("clean", Delete) {
     delete rootProject.buildDir
 }
 
diff --git a/packages/shared_preferences/shared_preferences_android/example/android/gradle/wrapper/gradle-wrapper.properties b/packages/shared_preferences/shared_preferences_android/example/android/gradle/wrapper/gradle-wrapper.properties
index b8793d3..cfe88f6 100644
--- a/packages/shared_preferences/shared_preferences_android/example/android/gradle/wrapper/gradle-wrapper.properties
+++ b/packages/shared_preferences/shared_preferences_android/example/android/gradle/wrapper/gradle-wrapper.properties
@@ -3,4 +3,4 @@
 distributionPath=wrapper/dists
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-7.0.2-all.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-7.6.1-all.zip