Support storing master user credentials in SSM

Features

• Add support to store master user creds in SSM

Breaking Change

• Minimum aws provider version 3.63.0

Adding attributes for major version upgrade

Couple of attributes like allow_major_version_upgrade and db_cluster_db_instance_parameter_group_name were missing in the implementation of the module which are required for upgrading the version of the postgres.

v2.4: Fixes the bug with upgrading engine version (#16)

Recently we were encountering the described error here:
https://github.com/terraform-aws-modules/terraform-aws-rds-aurora/issues/118
when we were upgrading from 10.11 to 10.14. It dropped the instances and then stopped right in the middle with a 400 - leaving everything in pieces behind :(.
I tried the fix locally by modifying the `terraform/apps/oma/.terraform/eu01/stg02-de/modules/oma.db/main.tf` adding the changes and it seems to work as expected.

v2.3: Fix error when user passes wrong (#15)

Co-authored-by: Max Williams <[email protected]>

Fix error about applying windows to instances

v2.0

Fix error about applying windows to instances (#12)

RDS CA cert option and correctly set backup_window

v1.9

Add ca_cert_identifier and missing backup_window on cluster resource …

Small Terraform 0.12 Fix

v1.8

Small Terraform 0.12 fix

Upgrade module to support Terraform 0.12

Merge pull request #10 from deliveryhero/terraform12

Upgrade module to support Terraform 0.12

allow extra SGs for the cluster

v1.6

Allowing adding extra SGs for the cluster (#9)

adding deletion protection

v1.5

Adding deletion protection option (#8)