x11-wm/cwm: Update to 7.4

• Take maintainership

ChangeLog:

2023-10-20: Ninth public release 7.4 of portable cwm.

Changes made between OpenBSD 7.3 and 7.4:

• Allow cwm(1) to cycle through windows of the same window class as the active window, default key binding to M-grave, respectively Alt-Tilde, like with other window managers.