Detecting virtualenv installation successfully

[arcsector]

Detecting virtualenv installation successfully

🗣 Description

Fixing #243

💭 Motivation and context

See #243 for context

🧪 Testing

Tested using pyenv in WSL2 without a pyenv-virtualenv binary in immediate path, despite having it installed properly and pyenv virtualenvs command working fine

✅ Pre-approval checklist

• This PR has an informative and human-readable title.
• Changes are limited to a single goal - eschew scope creep!
• All future TODOs are captured in issues, which are referenced
  in code comments.
• All relevant type-of-change labels have been added.
• I have read the CONTRIBUTING document.
• These code changes follow cisagov code standards.
• All relevant repo and/or project documentation has been updated
  to reflect the changes in this PR.
• All new and existing tests pass.

✅ Pre-merge checklist

• Revert dependencies to default branches.
• Finalize version.

✅ Post-merge checklist

• Create a release.

[mcdonnnj]

@arcsector The lack of Linux compatibility with that script is a long-standing, undocumented issue that is nice to see resolved. However, would you please re-create this pull request in cisagov/skeleton-generic? We use a repository inheritance system through our Lineage process and the ultimate "source of truth" for that script is in the repository I mentioned.

[arcsector]

Done - I'll close this PR since it sounds like this will be propgated from upstream.