Update required version of VS Code

Author: mrmlnc

package.json

@@ -6,7 +6,7 @@
   "publisher": "mrmlnc",
   "license": "MIT",
   "engines": {
-    "vscode": "^1.8.0"
+    "vscode": "^1.13.0"
   },
   "icon": "icon.png",
   "homepage": "https://github.com/mrmlnc/vscode-duplicate/blob/master/README.md",