Use Codecov's GitHub Action

[hugovk]

Changes proposed in this pull request:

• Codecov GitHub Action is now available for all three operating systems
• https://github.com/codecov/codecov-action
• There was a problem including the Pillow token in .codecov.yml: some of the build jobs in my fork were sent to Pillow's Codecov, not mine
• Plus fix so GHA macOS coverage is collected: needed to install lcov properly Done in GHA: Install lcov on macOS to report coverage #4217

[hugovk]

Yeah, this doesn't work, for the same reason we added the token to .codecov.yml in the first place: GHA won't allow forks access to secrets, namely secrets.CODECOV_TOKEN.

So there's no GHA coverage here (yet, but all GHA jobs have finished):

• https://codecov.io/gh/python-pillow/Pillow/commit/1ff3a501ef31552e1ef279b8554655977f1c2e0e/build.

Specific issue at Codecov GitHub Action:

• Is there a way to make this work with a PR from a fork codecov/codecov-action#29

General issue at GitHub Community:

• https://github.community/t5/GitHub-Actions/Make-secrets-available-to-builds-of-forks/m-p/30678/highlight/true#M508

Let's see what happens with the token re-added.

[nulano]

How about putting the token in the .yml files (hopefully temporarily)? I think using the GitHub action is cleaner; coverage currently doesn't work on Windows, and the Linux builds are received as 'Untitled' anyway.

[hugovk]

Yes, let's give it a go. Bullet point 3 will still be a problem, but the other bits are an improvement over the current situation.