nextSyncTime is not being updated when the schedule changes

[JohnStrunk]

Describe the bug nextSyncTime field in the CR isn't being updated if the trigger's schedule is changed. It's only being updated at the end of a sync cycle.

Steps to reproduce

• Deploy a source PVC to src/datavol

• Execute:

  $ ./bin/kubectl-volsync replication -r test create
  $ ./bin/kubectl-volsync replication -r test set-source --pvcname src/datavol
  $ ./bin/kubectl-volsync replication -r test set-destination --destination dst/datavol
  $ ./bin/kubectl-volsync replication -r test schedule --cronspec '0 * * * *'
  I0617 12:37:32.820563  388656 replication.go:381] waiting for keys & address of destination to be available
  I0617 12:37:37.829154  388656 replication.go:406] creating resources on Source

• A sync will be triggered and nextSyncTime gets set to the top of the next hour (as it should):

  status:
  conditions:
  - lastTransitionTime: "2022-06-17T16:37:52Z"
    message: Waiting for next scheduled synchronization
    reason: WaitingForSchedule
    status: "False"
    type: Synchronizing
  lastSyncDuration: 15.202170362s
  lastSyncTime: "2022-06-17T16:37:52Z"
  nextSyncTime: "2022-06-17T17:00:00Z"
  rsync: {}

• Edit the RS to have a '*/5' schedule: $ kubectl edit -n src replicationsource/datavol-jm7qj

• The nextSyncTime should be the nearest minute that is divisible by 5, but it's still top of the hour:

  apiVersion: volsync.backube/v1alpha1
  kind: ReplicationSource
  metadata:
  creationTimestamp: "2022-06-17T16:37:37Z"
  generation: 2
  labels:
  volsync.backube/relationship: 36610c53-a6f5-4acf-959b-a3756b035e5c
  name: datavol-jm7qj
  namespace: src
  resourceVersion: "18119"
  uid: 2a184ff9-2b7d-498a-ac89-b141ed86cacf
  spec:
  rsync:
  address: 10.96.48.66
  copyMethod: Clone
  sshKeys: datavol-jm7qj
  sourcePVC: datavol
  trigger:
  schedule: '*/5 * * * *'
  status:
  conditions:
  - lastTransitionTime: "2022-06-17T16:37:52Z"
  message: Waiting for next scheduled synchronization
  reason: WaitingForSchedule
  status: "False"
  type: Synchronizing
  lastSyncDuration: 15.202170362s
  lastSyncTime: "2022-06-17T16:37:52Z"
  nextSyncTime: "2022-06-17T17:00:00Z"
  rsync: {}

Expected behavior

Actual results

Additional context Discovered based on #268

There is also a related issue where a manual trigger is set, then removed, causing no further syncs.

[JohnStrunk]

/assign

I think I introduced this w/ the state machine re-write: #210

210 isn't in release-0.4, so no need to backport. :sweat_smile: