sysutils/onefetch: Update to 2.4.0

Changelog[1]:

• Improve the overall performance
• Make it easier for future contributors to add support for a new language.

[1] https://github.com/o2sh/onefetch/releases/v2.4.0

PR: 250091
Submitted by: Lewis Cook <vulcan@wired.sh> (maintainer)
Approved by: tcberner (mentor)
Differential Revision: https://reviews.freebsd.org/D26666