patch release 1.18.4

[jangorecki]

We got a deadline, so a new version will be on CRAN in a few days, including a fix for this issue.

Originally posted by @aitap in #7695

@TysonStanley looks like we need another release to CRAN. When preparing please ensure that issues assigned to that milestone reflect what will be submitted to CRAN. Especially I would like patch to frollapply not to be missed.

[aitap]

The underlying issue was fixed by #7664, now packported in 459ea65.

[TysonStanley]

Yes, can confirm the ERROR and due date May 13.

Thanks, @aitap. Will get this started tomorrow/this weekend. I'll also look for the patch for frollapply and include that as well.