test: fix test failure due to localhost being also ipv6

[ikonst]

On my MacOS machine:

% host localhost.   
localhost has address 127.0.0.1
localhost has IPv6 address ::1

This caused the "should handle connection error" test to fail, since the error was an AggregateError containing both the 127.0.0.1 and the ::1 failure.

To make this uniform across different test environments, I'm changing the hostname to an IPv4 IP address. (It might be worthwhile to test AggregateError behavior and IPv6 behavior but this is not the goal of this PR.)

Checklist

• I have ensured my pull request is not behind the main or master branch of the original repository.
• I have rebased all commits where necessary so that reviewing this pull request can be done without having to merge it first.
• I have written a commit message that passes commitlint linting.
• I have ensured that my code changes pass linting tests.
• I have ensured that my code changes pass unit tests.
• I have described my pull request and the reasons for code changes along with context if necessary.

[ikonst]

👋 @titanism

[ikonst]

@titanism could you take a look?

[titanism]

v7.1.0 released to npm – please try it out and let us know if it works for you 🎉

https://github.com/ladjs/supertest/releases/tag/v7.1.0

Thank you for your contributions 🙏

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