ci: add gh action workflow definition for F5 CLA automation

[TasoOneAsia]

Proposed changes

Adds a GH action workflow file (.github/workflows/f5-cla.yml) for F5 contributor license agreement (CLA) automation and compliance. This action is configured to target a shared signature store for F5 Open Source projects and will prompt contributors, upon pull request to main, to sign the F5 CLA if they have not already done so.

As part of the configuration for this project, the following GitHub usernames were whitelisted as maintainers:

• Dean-Coakley
• pleshakov
• lucacome

Checklist

Before creating a PR, run through this checklist and mark each as complete.

• [x] I have read the CONTRIBUTING guide
• [x] I have proven my fix is effective or that my feature works
• [x] I have checked that all unit tests pass after adding my changes
• [x] I have ensured the README is up to date
• [x] I have rebased my branch onto main
• [x] I will ensure my PR is targeting the main branch and pulling from my branch on my own fork

[TasoOneAsia]

@lucacome Should this get any additional reviews, or is this good to go?

[lucacome]

@TasoOneAsia we require two approvals

[pdabelf5]

Should this PR update the contributing guide to advise how to get approval for the F5 CLA?

[TasoOneAsia]

@pdabelf5 Good call 👍

I'll update CONTRIBUTING to mention the CLA requirements and the agreement process.

[TasoOneAsia]

Since this got the two approvals, I'll go ahead and squash + merge this on Monday if there are no objections.