Add support for OpenBSD 7.8

[lcheylus]

OpenBSD 7.8 release is now available => https://www.openbsd.org/78.html

Could you please add support for it?

[lcheylus]

@jacob-carlborg Please, could you release a new version with support of OpenBSD 7.8? I need to use this version in one of my GH workflows.

[jacob-carlborg]

Yes, working on it.