MNT: make pre-release notes script check if EDITOR is set

[nstelter-slac]

Description

Motivation and Context

closes #326

How Has This Been Tested?

Tested manually

Where Has This Been Documented?

don't think it's necessary for this

Pre-merge checklist

• [x] Code works interactively
• [x] Code contains descriptive docstrings, including context and API
• [ ] New/changed functions and methods are covered in the test suite where possible
• [x] Test suite passes locally
• [x] Test suite passes on GitHub Actions
• [x] Ran docs/pre-release-notes.sh and created a pre-release documentation page
• [x] Pre-release docs include context, functional descriptions, and contributors as appropriate

[nstelter-slac]

should prob also update the other pre-release scripts b4 closing issue: https://github.com/search?q=org%3Apcdshub+if+%24%7BEDITOR%7D&type=code

[nstelter-slac]

actually lets just only also update cookie-cutter for now: https://github.com/pcdshub/cookiecutter-pcds-python/pull/55

[ZLLentz]

Merging once the CI finishes churning