[WIP] DONT MERGE YET deps: update ibrowse to support inet6-only hosts

[dch]

Pulls in our custom ibrowse with inet6-only host support
from apache/couchdb-ibrowse#1

This will require tagging our ibrowse first with a matching
tag, I've proposed CouchDB-4.0.2 but anything goes.

Testing recommendations

Try replicating from an IPv6-only host.

Related Issues or Pull Requests

apache/couchdb-ibrowse#1

Checklist

• Code is written and works correctly;
• Changes are covered by tests;
• Documentation reflects the changes;

for docs, I propose to add this to change log only. If there's
another place you'd like it mentioned please let me know.

[wohali]

@dch I'd like to see this land at the same time with us supporting binding only to IPv6 addresses, and there being sufficient test suites to validate, though this may require running make check on a IPv6-enabled host.

But that's just a wish, you're the one doing the work :)

[wohali]

@dch any luck here? your tests are failing...

[dch]

closing this until I have a few days free to work through it