Upgrade RDS from 12.16 -> 14.9 in terraform

[jterry64]

Pull request checklist

Please check if your PR fulfills the following requirements:

• Make sure you are requesting to pull a topic/feature/bugfix branch (right side). Don't request your master!
• Make sure you are making a pull request against the develop branch (left side). Also you should start your branch off our develop.
• Check the commit's or even all commits' message styles matches our requested structure.
• Check your code additions will fail neither code linting checks nor unit test.

Pull request type

Please check the type of change your PR introduces:

• Bugfix
• Feature
• Code style update (formatting, renaming)
• Refactoring (no functional changes, no api changes)
• Build related changes
• Documentation content changes
• Other (please describe):

What is the current behavior?

DB version set to 12.16.

Issue Number: GTC-2082

What is the new behavior?

The DB has been manually upgraded to 14.9, but needs to reflect that in the terraform. So no real changes.

Does this introduce a breaking change?

• Yes
• No

Other information