chore: add funding to package.json (#42)

Ref: expressjs/discussions#356

Author: Phillip9587

package.json

@@ -15,6 +15,10 @@
     "http"
   ],
   "repository": "jshttp/range-parser",
+  "funding": {
+    "type": "opencollective",
+    "url": "https://opencollective.com/express"
+  },
   "devDependencies": {
     "deep-equal": "1.0.1",
     "eslint": "6.0.1",