CircleCI publishing macOS binary wheels fails

[hacklschorsch]

macOS (and probably also all other) wheels aren't being published:

https://app.circleci.com/pipelines/github/LeastAuthority/python-challenge-bypass-ristretto/313/workflows/9b6b7c89-6153-4d1b-a760-61f1f14a0b2c/jobs/1179

Package index credentials unavailable; skipping upload.

[hacklschorsch]

Maybe they are only published when CI runs on the master branch - and there it fails because CircleCI can't check out via SSH?

i.e. https://app.circleci.com/pipelines/github/LeastAuthority/python-challenge-bypass-ristretto/318/workflows/b226ee65-4018-4a4b-9a25-f3a0c193aa89/jobs/1234

Writing SSH key for checkout to "/Users/distiller/.ssh/id_rsa"
Writing SSH public key for checkout to "/Users/distiller/.ssh/id_rsa.pub"
Cloning git repository - [email protected]:LeastAuthority/python-challenge-bypass-ristretto.git
Cloning into '.'...
[email protected]: Permission denied (publickey).
fatal: Could not read from remote repository.

[hacklschorsch]

Fixing this (the publishing to PyPI) is going to fix #57 and PrivateStorageio/ZKAPAuthorizer#472

[hacklschorsch]

This is working as intended - only builds of the master branch should be uploaded
This is currently also broken and tracked in #67.