fix(package): update jsdom to version 13.1.0

Closes #27

Author: greenkeeper[bot]

package.json

@@ -23,7 +23,7 @@
   },
   "homepage": "https://github.com/integrations/html-to-mrkdown#readme",
   "dependencies": {
-    "jsdom": "^11.6.2",
+    "jsdom": "^13.1.0",
     "turndown": "^4.0.0-rc.3",
     "turndown-plugin-gfm": "1.0.1"
   },