Add support for the pull_request_target event in the upload_pr_documentation workflow

[regisss]

In Optimum we need to use the pull_request_target event to be able to access repo secrets to build PR docs. However, PR docs have not been uploaded since this change happened.
This PR adds support for this event type in the upload_pr_documentation workflow.

[sgugger]

cc-ing @coyotte508 as well as he designed the current system with @mishig25

Just adding the workflow won't necessarily give you access to secrets, it's a tiny bit tricky and they should be able to explain it better than me.

[regisss]

cc-ing @coyotte508 as well as he designed the current system with @mishig25

Just adding the workflow won't necessarily give you access to secrets, it's a tiny bit tricky and they should be able to explain it better than me.

Actually accessing secrets to build the documentation is not the issue here, sorry I should have been more accurate. PR docs are built properly, the problem is that they are not uploaded because the "Upload PR documentation" workflow is not triggered for pull_request_target events.

For instance, here the PR doc was built properly: https://github.com/huggingface/optimum/actions/runs/5843309088/job/15845336669?pr=1280
But docs are never uploaded: https://github.com/huggingface/optimum/actions/workflows/upload_pr_documentation.yml

[fxmarty]

@mishig25 @regisss How does it sound?

[regisss]

@mishig25 @regisss How does it sound?

@sgugger @mishig25 I think @coyotte508 is out on paternity leave till October 1st and we need this in Optimum to get the PR doc working, is there any solution before he comes back?

[sgugger]

You should ping Mishig offline to check out this PR, he doesn't seem to read his GitHub notifications.

[mishig25]

lgtm !