This will help us avoid breaking changes in the future, when CI events need to be modified, and CI broker instances need to cope with the event queues in their databases.

Previously we had

enum CiEvent {
    BranchCreated { ... },
    BranchUpdatee { ... },
    ....
}

Change that to:

enum CiEvent {
    V1(CiEventV1),
}

enum CiEventV1 {
    BranchCreated { ... },
    BranchUpdatee { ... },
    ....
}

This will allow us to add new version variants to CiEvent, without losing access to the already enqueued V1 events.

Signed-off-by: Lars Wirzenius liw@liw.fi