Should tackle #14026.
This will run a daily Github action and create a PR if there's a new
update in our TUF on `edge` or `stable`.
E.g. somebody releases 1.22.0 fleetd to `stable` on our TUF and the next
day this automation runs and will create a PR that updates the versions
in `orbit/TUF.md` (or they can run the workflow manually).
Am happy to amend the shape of `orbit/TUF.md` (or we can iterate later).
