add zamtel and airtel networks

Author: FredDominant

rave_android/src/main/res/values/strings.xml

@@ -194,6 +194,8 @@
     <string-array name="zm_mobile_money_networks">
         <item>Select network</item>
         <item>MTN</item>
+        <item>AIRTEL</item>
+        <item>ZAMTEL</item>
     </string-array>
 
     <!-- TODO: Remove or change this placeholder text -->

rave_java_commons/src/main/java/com/flutterwave/raveandroid/rave_java_commons/RaveConstants.java

@@ -91,6 +91,8 @@ public class RaveConstants {
     public static String mtn = "MTN";
     public static String tigo = "TIGO";
     public static String vodafone = "VODAFONE";
+    public static String airtel = "AIRTEL";
+    public static String zamtel = "ZAMTEL";
 
     public static String tokenNotFound = "token not found";
     public static String expired = "expired";

rave_presentation/src/main/java/com/flutterwave/raveandroid/rave_presentation/data/PayloadBuilder.java

@@ -1,5 +1,7 @@
 package com.flutterwave.raveandroid.rave_presentation.data;
 
+import android.util.Log;
+
 import com.flutterwave.raveandroid.rave_core.models.SavedCard;
 import com.flutterwave.raveandroid.rave_java_commons.Meta;
 import com.flutterwave.raveandroid.rave_java_commons.Payload;