Tower UI no longer shows revisions for downloaded pipelines.

[MatthiasZepper]

Fix for issue #2307 and some other bugs discovered along the way:

• nf-core download will now always create the latest branch to ensure that there is at least one branch in the repo. It will use the tag with the highest semantic version number. Otherwise, Tower's UI will fail to display the revisions.
• A bug has been fixed that caused a TypeError in prompt_singularity_cachedir_remote(). In the documentation, I had missed that a validation str must be wrapped into a callable object. Now, SingularityCacheFilePathValidator in utils.py handles the validation of the interactive input to --singularity-cache-index.
• In read_remote_containers(), I had missed that a call to prompt_singularity_cachedir_remote() still used the retry argument, even though I removed this argument from the final version of the function, because @mashehu had recommended a better way to implement the behaviour.
• In find_container_images() I had denoted a logical and as & even though Python uses and.
• In prompt_singularity_cachedir_remote() and summary_log, I have rephrased two messages to the user.

PR checklist

• This comment contains a description of changes (with reason)
• CHANGELOG.md is updated (Not required, since there had not been a release yet of the buggy code.)
• If you've fixed a bug or added code that should be tested, add tests!
• Documentation in docs is updated

[github-actions]

This PR is against the master branch ❌

• Do not close this PR
• Click Edit and change the base to dev
• This CI test will remain failed until you push a new commit

---

Hi @MatthiasZepper,

It looks like this pull-request is has been made against the MatthiasZepper/tools 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 MatthiasZepper/tools 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!

[codecov]

Codecov Report

Merging #2308 (8abe1a6) into dev (711d074) will decrease coverage by 0.08%.
The diff coverage is 50.00%.

@@            Coverage Diff             @@
##              dev    #2308      +/-   ##
==========================================
- Coverage   72.97%   72.89%   -0.08%     
==========================================
  Files          78       78              
  Lines        8732     8756      +24     
==========================================
+ Hits         6372     6383      +11     
- Misses       2360     2373      +13     

Impacted Files	Coverage Δ
nf_core/utils.py	81.40% <28.57%> (-0.66%)	⬇️
nf_core/download.py	61.68% <55.55%> (-0.24%)	⬇️

[mashehu]

why don't you use looseversion here?

[MatthiasZepper]

distutils module is unfortunately deprecated. Will therefore rewrite and use neither StrictVersion nor LooseVersion. Took a simplified Regex derived from the one in PEP386.