chore(node): update karma to 2.0.0

Also reduce karma log level on Travis to INFO.
Before, the log level was DEBUG, but it seems that
prior to karma 2.0.0, the debug messages were not outoput on Karma,
so this simply restores the status quo (and prevents cluttering the log).

karma-shared.conf.js

@@ -181,7 +181,6 @@ module.exports = function(config, specificOptions) {
   if (process.env.TRAVIS) {
     var buildLabel = 'TRAVIS #' + process.env.TRAVIS_BUILD_NUMBER + ' (' + process.env.TRAVIS_BUILD_ID + ')';
 
-    config.logLevel = config.LOG_DEBUG;
     // Karma (with socket.io 1.x) buffers by 50 and 50 tests can take a long time on IEs;-)
     config.browserNoActivityTimeout = 120000;
 

package.json

@@ -61,7 +61,7 @@
     "jasmine-node": "^2.0.0",
     "jasmine-reporters": "^2.2.0",
     "jquery": "^3.2.1",
-    "karma": "^1.7.0",
+    "karma": "^2.0.0",
     "karma-browserstack-launcher": "^1.2.0",
     "karma-chrome-launcher": "^2.1.1",
     "karma-firefox-launcher": "^1.0.1",