investigate why commits to php sample don't trigger devfile reg respins

In CRW-4136, a commit to php-simple repo did not trigger rebuilds of devfile reg, nor did rebuild of plugin reg cause a respin of devfile reg.

• missing GH actions on the php-hello-world sample repo?
• wrong credentials?

need to diff against another sample that DOES work for triggering respins to devfile reg.

Or maybe the devfile reg 3.x job is messed up somehow?