See forum thread here:
https://forums.opensuse.org/showthread.php/572114-Boot-fails-with-rd-luks-key-on-command-line

After upgrading a 15.3 system that uses "rd.luks.key" on the command line to
15.4, booting fails with this message:
```
dracut: Found <keyfile> on <keydevice>
dracut: luksOpen <crypted-device> luks-<UUID>
dracut: Using <keyfile> on <keydevice>
Usage: cryptsetup [-?Vqrvy] [-?|--help] [--usage] [-V|--version]
[--active-name=STRING]
...lots more...
[OPTION...] <action> <action-specific>
/sbin/cryptsetup: Unknown action.
```
Then it asks for the password.

The root cause seems to be this issue in upstream dracut:
https://github.com/dracutdevs/dracut/issues/1528

Bug ID	1201812
Summary	Boot fails with rd.luks.key on command line
Classification	openSUSE
Product	openSUSE Distribution
Version	Leap 15.4
Hardware	x86-64
OS	openSUSE Leap 15.4
Status	NEW
Severity	Normal
Priority	P5 - None
Component	Bootloader
Assignee	screening-team-bugs@suse.de
Reporter	conrad-novell.com@quisquis.de
QA Contact	qa-bugs@suse.de
Found By	---
Blocker	---