Fix: First-time contributor welcome workflow fails due to actions/github-script@v7 not being in allowed actions list

[harshitghagre]

What happened:
The "First-time contributor welcome" workflow (first-time-contributor.yaml) fails with
a startup error for all first-time contributors because actions/github-script@v7 is
not in the repository's allowed GitHub Actions list.

Error message:

The action actions/github-script@v7 is not allowed in pipe-cd/pipecd.
Issues all actions must be from a repository owned by your enterprise
or match one of the patterns: [...]

Impact:
Every first-time contributor sees a failing CI check on their PR, which can be
confusing and discouraging for new contributors.

References:

• Workflow file: .github/workflows/first-time-contributor.yaml (line 15)
• Example failing run: https://github.com/pipe-cd/pipecd/actions/runs/25036058302

[Ayushmore1214]

Thanks for pointing out this @harshitghagre I'll take a look on this soon!