Remove empty path components from output paths

[siddharthab]

GCS does not allow double slashes (//) in paths by default. Other cloud storage platforms also do not have a well-defined behavior for them.

PR checklist

• This comment contains a description of changes (with reason).
• If you've fixed a bug or added code that should be tested, add tests!
• If you've added a new tool - have you followed the pipeline conventions in the contribution docs
• If necessary, also make a PR on the nf-core/atacseq branch on the nf-core/test-datasets repository.
• Make sure your code lints (nf-core lint).
• Ensure the test suite passes (nextflow run . -profile test,docker --outdir <OUTDIR>).
• Usage Documentation in docs/usage.md is updated.
• Output Documentation in docs/output.md is updated.
• CHANGELOG.md is updated.
• README.md is updated (including new tool citations and authors/contributors).

[github-actions]

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Hi @siddharthab,

It looks like this pull-request is has been made against the siddharthab/atacseq master branch.
The master branch on nf-core repositories should always contain code from the latest release.
Because of this, PRs to master are only allowed if they come from the siddharthab/atacseq dev branch.

You do not need to close this PR, you can change the target branch to dev by clicking the "Edit" button at the top of this page.
Note that even after this, the test will continue to show as failing until you push a new commit.

Thanks again for your contribution!

[siddharthab]

Looks like this was fixed by #355.