a change to the network{cni{}} block means that
the user wants the network config to change,
and that only happens during initial alloc setup,
so we need to replace the alloc(s) to get
fresh network(s) to reconfigure from scratch.
e.g. a job plan diff like this
```
+/- Task Group: "g" (1 in-place update)
+ Network {
+ CNIConfig {
+ a: "ayy"
}
```
should instead be
```
+/- Task Group: "g" (1 create/destroy update)
+ Network {
+ CNIConfig {
+ a: "ayy"
}
```
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