CLI output option `-o` does not work as expected with `../../` paths

[MalteJanz]

The CLI option -o which is mainly used for local testing has currently a critical bug:

./ludtwig -o ./../../output/ ../../fixtures/migration

results in the writer writing to the following path:

./../../output/../../fixtures/migration/path/to/template/template.html.twig

the expected path should look like:

./../../output/fixtures/migration/path/to/template/template.html.twig