chore: Add upgrade path info for terraform platform modules release version 6

[tony-griffin]

Addresses DBTP-

Please add any relevant context for you pull request here, or delete this if none needed.

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Checklist:

Title:

• Scope included as per conventional commits
• Ticket reference included (unless it's a quick out of ticket thing)

Description:

• Link to ticket included (unless it's a quick out of ticket thing)
• Includes tests (or an explanation for why it doesn't)
• Includes any applicable changes to the documentation in this code base
• Includes link(s) to any applicable changes to the documentation in the DBT Platform Documentation (can be to a pull request)

Tasks:

• Trigger the pull request regression tests for this branch and confirm that they are passing

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 80.83%. Comparing base (d8c3720) to head (02106e9).

✅ All tests successful. No failed tests found.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #312   +/-   ##
=======================================
  Coverage   80.83%   80.83%           
=======================================
  Files           5        5           
  Lines         814      814           
=======================================
  Hits          658      658           
  Misses        156      156           

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