These define gems to use for kitchen, so no customization is needed, you can just copy these files from the template formula if they are outdated in your formula.
Check "driver" and "provisioner" section (probably nothing to change).
Upgrade "platforms" section. You can copy and paste the whole thing from the template formula, as you will pick from those to only run some platforms in the gitlab-ci config.
Check "verifier"section (probably nothing to change).
The "suite" section is specific to the formula, no need to edit it.
Check ".node_anchors" section (specially images).
In the "test stage", remove all instances from your current yml file, then select some instances from the template formula and add them.
Refer to the comment in the template formula's .gitlab-ci.yml about picking a few instances.
For example, all of these {Alma, CentOS, Rocky, Oracle} are RHEL based, and Fedora is the upstream, so you will probably be fine if you test only with Fedora and not the other ones.
At the time of writing (2025-04), I suggest testing against Salt images for all 3 branches (master, 3006-10, 3007-1) as they behave differently, due to the great module migration.
Beware : if you defined more than one test suite in kitchen.yml, or named your config suite somehing else than "default", you have to remove the default- prefix from the instance names in .gitlab-ci.yml.
AFAIK, you can just overwrite the whole file with the one from the template formula.
Check the yamllint files to include / exclude are OK for your formula.
For these files :
.rstcheck.cfg.rubocop.yml.salt-lint.yamllint
They may contain specific overrides for your formula, so you will have to check their contents and see if you need to apply updates.