Use hash of setup.py as cache key

[tkkuehn]

Proposed changes

The deploy action uses a cached environment, and the key to that cache is currently based on the hash of requirements.txt. Because of the change to requirements.txt in #145, that file no longer works as a key for the cache, so this PR sets it up to use setup.py instead.

Types of changes

What types of changes does your code introduce? Put an x in the boxes that apply

• Bugfix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionalitiy)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Other (if none of the other choices apply)

Checklist

Put an x in the boxes that apply. You can also fill these out after creating the PR. If you are unsure about any of the choices, don't hesitate to ask!

• Changes have been tested to ensure that fix is effective or that a feature works.
• Changes pass the unit tests
• Code has been run through black with the -l 79 flag.
• I have included necessary documentation or comments (as necessary)
• Any dependent changes have been merged and published

Notes

All PRs will undergo the unit testing before being reviewed. You may be requested to explain or make additional changes before the PR is accepted.

PR template was adopted from appium

[kaitj]

LGTM! Rerunning ensured cache was properly too - merging!