1.19.1 support
Version 2.0 seems to have some issues with 1.19.1. The completion itself works fine, but when trying to execute the command, the game doesn't seem to recognize the command: Unknown or incomplete command, see below for error.
Removing the commodore registration fixes the issue.
I did a little further investigation and it seems that the dummy command actually gets executed:
https://github.com/lucko/commodore/blob/25c9459494ef58be5d58c1e61bd2b044278e1aaf/src/main/java/me/lucko/commodore/CommodoreImpl.java#L139
If I remove the UnsupportedOperationException it actually executes that command but still does not propagate the command to bukkits command executor.
Fixed in commodore 2.1 / 98f39247bf37ae5e754589a60bfd0d6f5c35533d