`preferred_maintenance_window` from the variables isn't propagated to the `docdb_cluster_instance` resources

[sherifkayad]

Found a bug? Maybe our Slack Community can help.

Describe the Bug

Using the module and specificying a certain preferred_maintenance_window, that's set only on the cluster level and not the cluster instances. That should change to match.

Expected Behavior

The preferrred maintenance window should be the same on the cluster and its instances to give the user control when the database can be patched / changed.

Steps to Reproduce

N.A.

Screenshots

N.A.

Environment (please complete the following information):

Anything that will help us triage the bug will help. Here are some ideas:

• OS: WSL

Additional Context

N.A.

[sherifkayad]

I can happily work on a quick fix and submit a PR.