fix: Update F5 CLA workflow instructions

[mjang]

Proposed changes

Problem: F5 CLA Bot should automatically write usernames, etc. for users who agree to the F5 Contributor License Agreement.

The current bot is not working.

Solution: I've taken (most) a f5-cla.yml file from a repo where the process works (https://github.com/nginx/agent/blob/main/.github/workflows/f5-cla.yml) to modify a different version of the same file in this documentation repository.

Testing: Hopefully we can set up a test as part of this PR.

Unknown: could the problem be related to the new year.

GitHub issue:
closes: #37

Checklist

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

• I have read the contributing guidelines

• I have signed the F5 Contributor License Agreement (CLA)

• If applicable, I have added tests that prove my fix is effective or that my feature works

• If applicable, I have checked that any relevant tests pass after adding my changes

• I have updated any relevant documentation (README.md and CHANGELOG.md)

• I have rebased my branch onto main

• I will ensure my PR is targeting the main branch and pulling from my branch from my own fork

• If the change involves:

  • Code
  • Anything that resembles Personally identifying information (PII)
    • Make sure to use placeholders such as <username> in place of PII
  • URLs (watch for typosquatting)
  • Significant new/revised content

  In these cases, the change will require at least two (2) approvals before merging

[mjang]

Maybe N/R, since it worked here: #38 (comment)