support Debian 11 / Ubuntu 22

[shinebayar-g]

As others have reported in #45 Ubuntu 22 doesn't seem to work.

On the fresh setup, I'm seeing following output.

ubuntu@ufw-test-f3c5604:~$ ./ufw-docker-automated
2022/11/14 01:06:13 ufw-docker-automated: Connecting to the Docker API. Listening for events..
2022/11/14 01:06:13 ufw-docker-automated: Couldn't inspect container: Error: No such container: ufw Cleaning up ufw rule
2022/11/14 01:06:13 ufw-docker-automated: Deleting rule: ufw allow 22
2022/11/14 01:06:13 ufw error: exit status 1 ERROR: 'route delete NUM' unsupported. Use 'delete NUM' instead.

Fortunately, it's not actually deleting the allow 22 rule. 😓

[shinebayar-g]

Looks like this specific error message was a regression introduced in previous v0.9.0 release, fixed.