Workflow for PR run checks to manage secret usage

[withinfocus]

🎟️ Tracking

Internal change.

📔 Objective

See https://michaelheap.com/access-secrets-from-forks/ for background. This provides a check-run.yml reusable workflow that becomes a need for the two new scanning workflows that use secrets. When invoked by non-members of the organization, the check workflow will fail and short-circuit the scanners, therefore not failing on secret access. A member can then review the change for safety and manually run the workflows that failed or were skipped. This can serve as a pattern across all our repos that use secrets in workflows and we better collaborate with external contributors.

⏰ Reminders before review

• Contributor guidelines followed
• All formatters and local linters executed and passed
• Written new unit and / or integration tests where applicable
• Protected functional changes with optionality (feature flags)
• Used internationalization (i18n) for all UI strings
• CI builds passed
• Communicated to DevOps any deployment requirements
• Updated any necessary documentation (Confluence, contributing docs) or informed the documentation team

🦮 Reviewer guidelines

• 👍 (:+1:) or similar for great changes
• 📝 (:memo:) or ℹ️ (:information_source:) for notes or general info
• ❓ (:question:) for questions
• 🤔 (:thinking:) or 💭 (:thought_balloon:) for more open inquiry that's not quite a confirmed issue and could potentially benefit from discussion
• 🎨 (:art:) for suggestions / improvements
• ❌ (:x:) or ⚠️ (:warning:) for more significant problems or concerns needing attention
• 🌱 (:seedling:) or ♻️ (:recycle:) for future improvements or indications of technical debt
• ⛏ (:pick:) for minor or nitpick changes

[Hinton]

I don't believe we need pull_request, target should run on both forks and local PRs just in a different context https://docs.github.com/en/actions/using-workflows/events-that-trigger-workflows#pull_request_target

[withinfocus]

Based on my testing it didn't work, but I'll remove that for the moment and we merge to see what really happens.

[Hinton]

Let's test it.