Android 12 updates

* Updated gradle version and dependencies
* Bumped compileSdkVersion and targetSdkVersion to 31
* Added support for updates without user action
* Bumped versionCode and versionName

Changes required by API level 31:
 * Added explicit exported tags to activities and receivers
 * Added explicit IMMUTABLE|MUTABLE flags to PendingIntents

build.gradle

@@ -32,7 +32,7 @@ buildscript {
     ext.navigation= "2.3.4"
 
     dependencies {
-        classpath ("com.android.tools.build:gradle:4.1.3")
+        classpath ('com.android.tools.build:gradle:7.0.3')
         classpath ("org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin")
         classpath ("androidx.navigation:navigation-safe-args-gradle-plugin:$navigation")
     }