[`saltstack/salt-bootstrap`] Assist in effort to get OpenBSD `git`-based installations working (to allow for `master`-branch Vagrant boxes)

[myii]

A review of this PR has already been done:

• OpenBSD: correct post-Neon package names to python3 versions saltstack/salt-bootstrap#1801 (review)

If a resolution is found, then work towards building OpenBSD master Vagrant boxes to use for CI testing across formulas.

[myii]

Try installing py3-zmq to get OpenBSD git installs working

Saw the package mentioned in the main comment here:

• OpenBSD git installation fails to compile pyzmq saltstack/salt-bootstrap#1802

Trying it out got further in the process until this error:

 * DEBUG: Running 'python3 setup.py --salt-config-dir=/etc/salt --salt-cache-dir=/var/cache/salt -v bdist_wheel'
3005+0na.98cd52d
usage: setup.py [global_opts] cmd1 [cmd1_opts] [cmd2 [cmd2_opts] ...]
   or: setup.py --help [cmd1 cmd2 ...]
   or: setup.py --help-commands
   or: setup.py cmd --help

error: invalid command 'bdist_wheel'

Tried logging in and pip installing wheel but then hit another roadblock:

 * DEBUG: Running 'pip3.8 install --no-deps --force-reinstall --prefix=/usr /tmp/git/deps/salt*.whl'
WARNING: The directory '/home/vagrant/.cache/pip' or its parent directory is not owned or is not writable by the current user.
         The cache has been disabled. Check the permissions and owner of that directory.
         If executing pip with sudo, you may want sudo's -H flag.
Processing ./deps/salt-3005+0na.98cd52d-py3-none-any.whl
Installing collected packages: salt
Successfully installed salt-3005+0na.98cd52d
/usr/local/lib/python3.8/site-packages/pip/_internal/commands/install.py:234:
UserWarning: Disabling all use of wheels due to the use of --build-option / --global-option / --install-option.
  cmdoptions.check_install_build_global(options)

[myii]

An issue has been reported upstream:

• Bundled libzmq fails on OpenBSD 7.1 zeromq/pyzmq#1690