Updated to address comment regarding pip installer not working by changing from bash to zsh.

[MartinLBeacham]

…changing from bash to zsh. Refactored code for readability.

Describe the changes you have made:

Reference any relevant issues (e.g. "Fixes #000"):

Pre-Submission Checklist (optional but appreciated):

• [ ] I have included relevant documentation updates (stored in /docs)
• [X] I have read docs/CONTRIBUTING.md
• [X] I have read docs/ROADMAP.md

OS Tests (optional but appreciated):

• [ ] Tested on Windows
• [X] Tested on MacOS
• [ ] Tested on Linux