Add deprecated and requiresApi annotations

This is to flag that these should be cleaned up when support for
Android API 22 and older is dropped.

OneSignalSDK/onesignal/src/main/java/com/onesignal/GenerateNotificationOpenIntent.kt

@@ -3,6 +3,7 @@ package com.onesignal
 import android.app.PendingIntent
 import android.content.Context
 import android.content.Intent
+import androidx.annotation.RequiresApi
 
 class GenerateNotificationOpenIntent(
  private val context: Context,
@@ -35,6 +36,7 @@ class GenerateNotificationOpenIntent(
  )
  }
 
+ @RequiresApi(android.os.Build.VERSION_CODES.M)
  private fun getNewBaseIntentAndroidAPI23Plus(): Intent {
  return Intent(
  context,
@@ -43,6 +45,7 @@ class GenerateNotificationOpenIntent(
  }
 
  // See NotificationOpenedReceiverAndroid22AndOlder.java for details
+ @Deprecated("Use getNewBaseIntentAndroidAPI23Plus instead for Android 6+")
  private fun getNewBaseIntentAndroidAPI22AndOlder(): Intent {
  val intent = Intent(
  context,