update android sdk version.

android/build.gradle

@@ -6,6 +6,7 @@ buildscript {
     repositories {
         google()
         jcenter()
+        mavenCentral()
     }
 
     dependencies {
@@ -18,6 +19,7 @@ rootProject.allprojects {
     repositories {
         google()
         jcenter()
+        mavenCentral()
     }
 }
 
@@ -42,7 +44,7 @@ android {
 
 dependencies {
     implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version"
-    api 'com.tencent.mm.opensdk:wechat-sdk-android-without-mta:6.6.22'
+    api 'com.tencent.mm.opensdk:wechat-sdk-android-without-mta:6.7.4'
     implementation 'org.jetbrains.kotlinx:kotlinx-coroutines-core:1.3.9'
     implementation 'org.jetbrains.kotlinx:kotlinx-coroutines-android:1.3.9'
     implementation 'androidx.appcompat:appcompat:1.2.0'

example/android/build.gradle

@@ -3,10 +3,11 @@ buildscript {
     repositories {
         google()
         jcenter()
+        mavenCentral()
     }
 
     dependencies {
-        classpath 'com.android.tools.build:gradle:3.6.3'
+        classpath 'com.android.tools.build:gradle:4.1.3'
         classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
     }
 }
@@ -15,6 +16,7 @@ allprojects {
     repositories {
         google()
         jcenter()
+        mavenCentral()
     }
 }
 

example/android/gradle/wrapper/gradle-wrapper.properties

-#Tue Oct 20 17:14:58 CST 2020
+#Sat Jun 26 08:02:17 CST 2021
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-6.1.1-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-6.5-bin.zip