If you are trying to use htmlize, download the file[0] to src directory, such that htmlize package is available as ~/web/src/htmlize.el

Now run emacs:

  ~/web$ emacs --batch -q -l src/htmlize.el\
  -l src/my-web.el -f org-publish-all

See https://gitlab.com/sadiq/sadiq.gitlab.io/blob/master/.gitlab...

You can simply download/clone the complete repo[1] and run the above command from its root directory.

[0] https://github.com/hniksic/emacs-htmlize/blob/master/htmlize...

[1] https://gitlab.com/sadiq/sadiq.gitlab.io