update Carelink EU with issue#18

mddub/minimed-connect-to-nightscout#18
Outlines some major changes in EU carelink as of 28.06.2020.

This patch updates the module with the information provided.

carelink.js

@@ -8,6 +8,7 @@ var _ = require('lodash'),
 var logger = require('./logger');
 
 var DEFAULT_MAX_RETRY_DURATION = module.exports.defaultMaxRetryDuration = 512;
+var USE_EU = process.env['MMCONNECT_SERVER'] === 'EU' ? true : false;
 if (process.env['MMCONNECT_SERVER'] === 'EU') {
   var carelinkServerAddress = "carelink.minimed.eu";
 } else {
@@ -19,6 +20,12 @@ var CARELINK_AFTER_LOGIN_URL = 'https://' + carelinkServerAddress + '/patient/ma
 var CARELINK_JSON_BASE_URL = 'https://' + carelinkServerAddress + '/patient/connect/ConnectViewerServlet?cpSerialNumber=NONE&msgType=last24hours&requestTime=';
 var CARELINK_LOGIN_COOKIE = '_WL_AUTHCOOKIE_JSESSIONID';
 
+var DEFAULT_OAUTH = process.env['USE_PRE_2020_OAUTH_EU'] == '1' ? false : true;
+if (DEFAULT_OAUTH && USE_EU) {
+  CARELINK_SECURITY_URL = 'https://mdtlogin.medtronic.com/mmcl/auth/oauth/v2/authorize/login';
+  CARELINK_JSON_BASE_URL = 'https://carelink.minimed.eu/patient/connect/data?cpSerialNumber=NONE&msgType=last24hours&requestTime';
+}
+
 var carelinkJsonUrlNow = function() {
   return CARELINK_JSON_BASE_URL + Date.now();
 };