Investigate and document 'next version' testing of example apps

[jennifer-shehane]

We have a process around testing 'example' apps for breaking change releases, so that we can update example apps ahead of release and test all of them with upcoming breaking changes.

Each time we do a breaking release, the team is confused about how this works because it is poorly documented and the logic exists across several repositories and is unclear on how the coordinate.

We want this clearly documented so that engineers and DX know how to coordinate this in the future. Especially:

• What to name branches on example apps
• Which example apps this works on
• How to set 'next version'

[cypress-bot]

The code for this is done in cypress-io/cypress#19157, but has yet to be released.
We'll update this issue and reference the changelog when it's released.