Test broken on NodeJS v18

[wolfy1339]

The cause would be #442

FAIL test/request.test.ts (8.87 s)
  ● request() › options.request.signal is passed as option to fetch
    expect(received).toMatch(expected)
    Expected pattern: /\bsignal\b/i
    Received string:  "AbortSignal: Expected funk to be an instance of AbortSignal."
      587 |
      588 |       .catch((error) => {
    > 589 |         expect(error.message).toMatch(/\bsignal\b/i);
          |                               ^
      590 |         expect(error.message).toMatch(/\bAbortSignal\b/i);
      591 |       });
      592 |   });
      at test/request.test.ts:589:31

[wolfy1339]

node-fetch/node-fetch#1554
That offers some insight with the error message

[wolfy1339]

Fixed by #509