add changelog descrtiption of last few commits
v2.1.9
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* server-status no longer leaves the "activity" column empty when a renewal is ongoing.
+ * server-status activity: report a renewal as "pending" when it is due but no job has been
+ started yet.
* removed the "valid after" time as this was confusing. The new certificate is already
valid, only it is recommeneded to wait with the actication a bit. Admins are probably
better aware what the clock skew requirements of their site are.
