Update kotlin to 1.6.10 to avoid build warnings

Author: danilobuerger

android/build.gradle

@@ -39,7 +39,7 @@ buildscript {
             ? rootProject.ext['kotlinVersion']
             : rootProject.hasProperty('AsyncStorage_kotlinVersion')
             ? rootProject.properties['AsyncStorage_kotlinVersion']
-            : '1.5.31'
+            : '1.6.10'
 
     repositories {
         google()
@@ -116,8 +116,8 @@ dependencies {
 
     if (useNextStorage) {
         def room_version = getVersionOrDefault('AsyncStorage_next_roomVersion', '2.4.2')
-        def coroutines_version = "1.5.2"
-        def coroutinesTest_version = "1.5.2"
+        def coroutines_version = "1.6.0"
+        def coroutinesTest_version = "1.6.0"
         // if we don't provide explicit dependency on reflection, kotlin plugin
         // would add one automatically, probably a version that is not compatible with
         // used kotlin

website/docs/advanced/Next.md

@@ -46,7 +46,7 @@ See [Configuration](#configuration) section below to learn more about setting di
 buildscript {
     ext {
         // other extensions
-+        kotlinVersion = '1.5.31'
++        kotlinVersion = '1.6.10'
     }
 
     dependencies {
@@ -67,19 +67,19 @@ AsyncStorage_useNextStorage=true
 
 **Kotlin version**
 
-Next storage is tested against Kotlin version `1.5.31`. 
+Next storage is tested against Kotlin version `1.6.10`. 
 You can specify different version, in one of two ways:
 
 - add `kotlinVersion` extension to the `rootProject`:
 
 ```groovy
-rootProject.ext.kotlinVersion = '1.5.31'
+rootProject.ext.kotlinVersion = '1.6.10'
 ```
 
 - specify `AsyncStorage_kotlinVersion` in `gradle.properties`:
 
 ```groovy
-AsyncStorage_kotlinVersion=1.5.31
+AsyncStorage_kotlinVersion=1.6.10
 ```
 
 **Room**