Add comma to package.json icon entry for JSON syntax compliance

Author: dermatz

package.json

@@ -4,7 +4,7 @@
   "description": "A Visual Studio Code extension to view and manage Magento log files.",
   "version": "1.0.1",
   "publisher": "MathiasElle",
-  "icon": "resources/logo.png"
+  "icon": "resources/logo.png",
   "repository": {
     "type": "git",
     "url": "https://github.com/dermatz/vscode-ext-magento-log-viewer"