Deploy of documentation is not made if the branch is from a fork

[ameligrana]

Somehow, the deploy of the docs doesn't succeed if the branch is from a fork as in a branch from main:

e.g. here there is one https://juliadynamics.github.io/Agents.jl/previews/PR1019/

but here there is not https://juliadynamics.github.io/Agents.jl/previews/PR1143/

where PR1019 was done from a branch from main and PR1143 was not

[Datseris]

The reason there is no deployment is because the PR author does not have push access to the repo. I think we can safely close this, it has always been like that.