PreviousAttemptURL is the API URL of the previous attempt of this run, e.g. ".../actions/runs/{run_id}/attempts/{attempt-1}".
It is set only when the current attempt is > 1 (i.e. a rerun). For the first attempt, or for legacy runs that pre-date ActionRunAttempt, it is null.
repository_idinteger
rerun_urlstring
run_attemptinteger
RunAttempt is 1-based for runs created after ActionRunAttempt was introduced.
A value of 0 is a legacy-only sentinel for runs created before attempts existed
and indicates no corresponding /attempts/{n} resource is available.