Adding github token auth to get_pr_merged_labels.sh

[nccatoni]

Motivation

Changes

Workflow

1. ⚠️ Create your PR as draft ⚠️
2. Work on you PR until the CI passes
3. Mark it as ready for review
   • Test logic is modified? -> Get a review from RFC owner.
   • Framework is modified, or non obvious usage of it -> get a review from R&P team

🚀 Once your PR is reviewed and the CI green, you can merge it!

🛟 #apm-shared-testing 🛟

Reviewer checklist

• Anything but tests/ or manifests/ is modified ? I have the approval from R&P team
• A docker base image is modified?
  • the relevant build-XXX-image label is present
• A scenario is added, removed or renamed?
  • Get a review from R&P team

[github-actions]

CODEOWNERS have been resolved as:

.github/chainguard/self.gitlab-read.sts.yaml                            @DataDog/system-tests-core
.gitlab-ci.yml                                                          @DataDog/system-tests-core
utils/scripts/get_pr_merged_labels.sh                                   @DataDog/system-tests-core