## Issue being fixed or feature implemented
This adds a check that ensures branches merge cleanly into master via a
ff-only
## What was done?
Added a GitHub action created via gpt-4 :)
## How Has This Been Tested?
https://github.com/PastaPastaPasta/dash/actions/runs/4703432752/jobs/8341923994
and
https://github.com/PastaPastaPasta/dash/actions/runs/4703457936/jobs/8341980146
for expected pass and expected fail
## Breaking Changes
None, should be back ported to v19.x branch when we get the chance.
## Checklist:
<!--- Go over all the following points, and put an `x` in all the boxes
that apply. -->
- [ ] I have performed a self-review of my own code
- [ ] I have commented my code, particularly in hard-to-understand areas
- [ ] I have added or updated relevant unit/integration/functional/e2e
tests
- [ ] I have made corresponding changes to the documentation
**For repository code-owners and collaborators only**
- [x] I have assigned this pull request to a milestone
