change std:string to String

ble-client-01/ble-client-01/ble-client-01.ino

@@ -96,7 +96,8 @@ bool connectToServer() {
 
     // Read the value of the characteristic.
     if(pRemoteCharacteristicRead->canRead()) {
-      std::string value = pRemoteCharacteristicRead->readValue();
+      //std::string value = pRemoteCharacteristicRead->readValue();
+      String value = pRemoteCharacteristicRead->readValue();
       Serial.print("The characteristic value was: ");
       Serial.println(value.c_str());
     }