Add syncCellularTime() public method

Author: pennam

src/ArduinoCellular.cpp

@@ -158,6 +158,10 @@ Time ArduinoCellular::getCellularTime(){
     return getTimeStruct(true);
 }
 
+bool ArduinoCellular::syncCellularTime(){
+    // Sync the time with the network NTP service
+    return syncNTPServer(true) == 0 ? true : false;
+}
 
 void ArduinoCellular::sendSMS(String number, String message){
     modem.sendAT("+CMGF=1"); 

src/ArduinoCellular.h

@@ -158,13 +158,19 @@ class ArduinoCellular {
          * @return The GPS location. If the location is not retrieved, the latitude and longitude will be 0.0.
          */
         Geolocation getGPSLocation(unsigned long timeout = 60000);
-        
+
         /**
          * @brief Gets the current time from the network.
          * @return The current time.
          */
         Time getCellularTime();
 
+        /**
+         * @brief Sync the modem time using NTP service.
+         * @return True  on success false otherwise.
+         */
+        bool syncCellularTime();
+
         /**
          * @brief Gets the current time from the GPS module.
          * @return The current time.