Update superagent dependecy to avoid deprecation warnings

[johnkrzywanek]

Hi, I am experiencing the following deprecation warning:

DEP0066] DeprecationWarning: OutgoingMessage.prototype._headers is deprecated

on chai-http requests.

After a quick investigation that is an issue that was resolved in the latest version of superagent (5.1.2) forwardemail/superagent#1502

Is there a reason for locking the superagent to version 3.x?

  "dependencies": {
...
    "@types/superagent": "^3.8.3",
...
    "superagent": "^3.7.0"
  },

from https://github.com/chaijs/chai-http/blob/master/package.json

If not, I am happy to add a PR to remove this lock

[austince]

Hey, thanks for the issue! I'm not sure exactly what breaking changes are in superagent >3, but our use of superagent is mostly in https://github.com/chaijs/chai-http/blob/master/lib/request.js. Do you still have time to add a PR/ would you mind checking if our usage is compatible?

[gian1200]

Hi. What's the status of this issue? Looks fixed but not released (?)