fix(package): update jsdom to version 15.2.0

Closes #5

Author: greenkeeper[bot]

package.json

@@ -31,7 +31,7 @@
     "css": "^2.2.1",
     "html-minifier": "^3.5.12",
     "is-absolute-url": "^2.1.0",
-    "jsdom": "^13.2.0",
+    "jsdom": "^15.2.0",
     "request": "^2.85.0",
     "request-image-size": "^2.1.0",
     "request-promise-native": "^1.0.5",