databases/pecl-couchbase: Update from 2.3.3 to 2.4.2

• Changelog: https://pecl.php.net/package/couchbase

• Update BUILD_DEPENDS

*While here:

• Switch to DISTVERSION
• Pet portlint

PR: 225248
Submitted by: johnpupu@gmail.com (maintainer)
Approved by: mentors (implicit)