Fix GitHub pages

[Zen0x7]

As peaceiris/actions-gh-pages README describes:

permissions:
    contents: write

is required. In other hand, without that, the step will fail.

Also a jump to the version 4 is recommended.

Basically because i did a test on the action without this change, just doesn't work:

Anyways, thanks so much @TheLartians.

[TheLartians]

Thanks a lot for the fix @Zen0x7 and sorry for the late review! The changes look good, however it seems that GitHub Actions are not starting running in this PR for some reason, even after merging with main. Could it be that you need to enable Actions on your fork?

[Zen0x7]

@TheLartians

I was able to enable actions and ran the github pages build pipeline, the result is the following:

https://github.com/Zen0x7/ModernCppStarter/actions/runs/12613562762/job/35151550642

Don't know what to do in this phase...

By the way, seems like pipeline is failing for other reason different than permissions.

[TheLartians]

By the way, seems like pipeline is failing for other reason different than permissions

Yeah seems that installing Doxygen using homebrew is failing for some reason. I've updated the workflow to use ubuntu and the ssciwr/doxygen-install action.

[TheLartians]

Thanks for the fix!