npm: bump yargs to 13.3.0 (#205)

Closes #204

Author: eternalmatt

package-lock.json

@@ -37,7 +37,7 @@
     "spawn-command": "^0.0.2-1",
     "supports-color": "^4.5.0",
     "tree-kill": "^1.2.1",
-    "yargs": "^12.0.5"
+    "yargs": "^13.3.0"
   },
   "devDependencies": {
     "coveralls": "^3.0.4",