Merge pull request #14 from arduino/chore/APP-1498-update-mqtt

chore(react-native): app-1498 Upgrade mqtt to 4.2.4

Author: balsick

android/build.gradle

@@ -137,4 +137,4 @@ dependencies {
 
   // Paho MQTT
     implementation 'androidx.legacy:legacy-support-v4:1.0.0'
-    implementation 'com.github.hannesa2:paho.mqtt.android:4.0'}
+    implementation 'com.github.hannesa2:paho.mqtt.android:4.2.4'}