Drop Python 3.7

[kaydeearts]

Description

⚠️ Starting April 3, 2023, the AFDKO will require Python 3.8 or later. Due to our dependencies already dropping support and requiring Python 3.8 in their latest versions, we will also be dropping Python 3.7 support on April 3, 2023.

Checklist:

• I have followed the Contribution Guidelines
• I have added test code and data to prove that my code functions correctly
• I have verified that new and existing tests pass locally with my changes
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation

[miguelsousa]

@kaydeearts I've removed 3.7 from the list of required status checks. (GH Settings > Branches > Branch protection rules)

[kaydeearts]

@miguelsousa thanks so much! I was wondering where I could remove that 😄

[josh-hadley]

Looks good 🚀

[kaydeearts]

Bumping fonttools to the latest version requires some test output changes. I'll put that into a different PR and keep this to just dropping Python 3.7.