Ignore draft changes when computing Mean Time metrics

[TristanCacqueray]

Should draft changes be taken into account? Perhaps a new set of metric without draft could be provided, e.g. by adding a "not status:draft" filter here:

monocle/src/Monocle/Backend/Queries.hs

Line 1725 in b6b114f

<$> withEvents [documentType dt] (withFlavor qf firstEventOnChanges)

[TristanCacqueray]

That might be more complicated because the draft status is stored in the change. So it seems like we would need a new event type to record the transition between draft created and change created (e.g. ready to be reviewed).

[morucci]

It seems that, regarding the GitHub crawler:

• CONVERT_TO_DRAFT event: https://docs.github.com/en/graphql/reference/objects#converttodraftevent
• READY_FOR_REVIEW event: https://docs.github.com/en/graphql/reference/objects#readyforreviewevent

could be handled to set a ready_at field. Then we could leverage that field when computing the mean time to merge metric.