Update variables.tf

[PatriceWallace]

what

• Describe high-level what changed as a result of these commits (i.e. in plain-english, what do these changes mean?)
• Use bullet points to be concise and to the point.

why

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• Describe why these changes were made (e.g. why do these commits fix the problem?)
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references

• Link to any supporting github issues or helpful documentation to add some context (e.g. stackoverflow).
• Use closes #123, if this PR closes a GitHub issue #123

[joe-niland]

Hi @PatriceWallace
Thanks for the contribution. I can't see how this change relates to this module. Closing.