According to upstream gitea nodejs 16 has broken them and there isn't
much they can do other than using nodejs 14 for the moment. Use 14 in
our image builds to keep our dockerfile buildable.
See https://github.com/go-gitea/gitea/issues/16604 for more info.
Change-Id: I143c3e67f354d220614136905e8b598cd6d2ad61
28736e31ba