correction of README.md

- fillform.com no longer exists
- httpbingo.org changed some responses
- Several tests needed error handling so they fail instead of timing out.
- Some error handling updates were needed for modern node versions.
- Longer timeouts were needed for test suite reliability with remote hosts.

request 2.88.1 used tough-cookie 2.5.0 as a dependency
In that version of tough-cookie, the `getCookies()`
method was not a sync method. Either you had to call
a callback or use `getCookiesSync()`.

postman-request also uses a tough-cookie-compatible fork.

Ref: https://github.com/request/request/blob/3c0cddc7c8eb60b470e9519da85896ed7ee0081e/package.json#L47
Ref: https://www.npmjs.com/package/tough-cookie/v/2.5.0

postman-request is a fork of request 2.88.1, with only some security
and bug fixes applied.

All tested passed as-is with exception one that appeared it needed to
be updated to be compatible with the last released version of `request`
as well.

This commit changes the dep security fixes that can be fixed by
by `npm audit fix`

More aggresively upgrades vulnerable deps. These are all
"devDeps", and all tests pass after the update.

It was no longer actively being used.

`coveralls` depended on deprecated `request` module which in turn
depended on vulnerable `request` module.

test: fix test failures

address dep vulns