added read-all permission status to Github Actions Workflow

[Cyan4973]

Following recommendations from @gabibguti and @t-mat at #806

[gabibguti]

Just FYI permissions: read-all is different than permissions: contents: read.

read-all grants read access to actions, checks, contents and other scopes, while contents: read gives read access only to contents scope and none access to all other scopes. The second option is more similar to the setting "Read repository content".

That said, I don't see any problems granting read-all in this case. 👍

https://docs.github.com/en/actions/security-guides/automatic-token-authentication#permissions-for-the-github_token

[Cyan4973]

Thanks for explaining the distinction @gabibguti , it's very clear !

There's no reason to give more rights than necessary,
let's change it to content: read as initially suggested by @t-mat .