Allow empty argument for --dane #196

Job	Run time
Running unit tests on debian:10	1m 10s
Running unit tests on debian:11	53s
Running unit tests on macos-12	1m 13s
Running unit tests on debian:12	1m 9s
Running unit tests on macos-13	2m 10s
Running unit tests on debian:testing	1m 4s
Running unit tests on macos-latest	58s
Running unit tests on ubuntu:18.04	56s
Running RPM tests on fedora:39	52s
Running unit tests on ubuntu:20.04	57s
Running RPM tests on fedora:40	32s
Running RPM tests on fedora:41	29s
Running RPM tests without bash completion on fedora:39	1m 2s
Running unit tests on ubuntu:22.04	1m 7s
Running RPM tests without bash completion on fedora:40	33s
Running unit tests on alpine:3.13	33s
Running RPM tests without bash completion on fedora:40	44s
Running unit tests on fedora:39	1m 50s
Running RPM tests without bash completion on fedora:41	27s
Running unit tests on fedora:40	2m 24s
Running unit tests on fedora:41	1m 34s
	22m 37s

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