Get DORA (DevOps Research and Assessment) metrics for the authenticated user's team.
Returns deployment frequency, lead time for changes, change failure rate, and mean time
to recovery with period-over-period comparison and performance categories (Elite/High/Medium/Low).
The comparison fields are null when the team's history doesn't reach back over the previous
period; say nothing about change rather than inferring it.
Lead time is null when no merged pull request could be matched to a deploy, and recovery time
is null when no failure was recovered from; both are then categorised "No Data", not rated.
The overall rating averages only the measured metrics and is "No Data" with fewer than three.