Replace pull_request_target with pull_request

[Sandhya1236]

Hi all,

Please replace insecure usage of pull_request_target. Here is at least one instance:

llama.cpp/.github/workflows/labeler.yml

Line 3 in ff5ef82

- pull_request_target

We have pull_request_target guidance and suggested alternatives on the OSDO site at go/github-pull-request-target.

I have limited pull requests to internal QC members only for the time being until this is addressed. Reach out to go/ossops if you have questions or concerns.

Thanks,
OSSOps.