Create branch vendor/dhcpcd and import dhcpcd release 9.4.1

[woodsb02]

Summary

Followed the committer's guide instructions to create a new vendor branch:
https://docs.freebsd.org/en/articles/committers-guide/#_creating_a_new_vendor_branch

Test Plan

Review state of git branch and seek approval of a src committer before committing.

$ git log
commit f0601cdb52cc961f2c8fb28bc72ad7dcf37af335 (HEAD -> vendor/dhcpcd, tag: vendor/dhcpcd/9.4.1, dhcpcd/vendor/dhcpcd)
Author: Ben Woods <[e-mail]>
Date: Sun Aug 14 13:36:04 2022 +0800

                                           
Import dhcpcd 9.4.1

$ git branch
+ main

• vendor/dhcpcd

$ git tag -n9 vendor/dhcpcd/9.4.1
vendor/dhcpcd/9.4.1 Tag dhcpcd 9.4.1

[philip]

This looks good.

Approved by: philip

[woodsb02]

Committed.
https://cgit.freebsd.org/src/commit/?h=vendor/dhcpcd&id=96dba636abec6d5451820add99300bda2ca6d86a