#### Affinity and spread updates are non-destructive

We fixed a scheduler bug so that updates to `affinity` and
`spread` blocks are no longer destructive. After a job update that changes only
these blocks, existing allocations remain running with their job version
incremented. If you were relying on the previous behavior to redistribute
workloads, you can force a destructive update by changing fields that require
one, such as the `meta` block.
