Document how to sign mac builds (StandaloneOSX)

[davidmfinol]

Context

Mac builds require codesign in order for users to be able to be easily download and run.
Users are confused about why they are unable to download and run their mac builds.

Suggested solution

Create a page at https://game.ci/docs/github/deployment/mac that would detail the codesign process, and how to upload builds to the Mac App Store.

Considered alternatives

Per game-ci/unity-builder#329, users may be able to bypass code-signing by running these commands on the downloaded artifact:

chmod +x ~/Downloads/StandaloneOSX.app/Contents/MacOS/<app>
xattr -d com.apple.quarantine ~/Downloads/StandaloneOSX.app/Contents/MacOS/<app>

But it would be better to teach users how to sign their app, so that they are able to distribute their app.

Additional details

I share my codesign process here: game-ci/unity-builder#329 (comment)

[Zh4rsiest]

For others (newbies like me about code signing) not to waste time with implementing the above lines as a job in your GitHub actions, don't do it, because it's worthless. On newer OS, the file gets quarantined after downloading and I learned this the hard way 😄 Maybe it's self explanatory, but could save some time for others.

On the other hand, I'm planning to do a minimalistic MacOS application where you could drag and drop your file and will remove the quarantine. I'll post my update here once it's done!