Fix syntax error in example

[vanastassiou]

Fixes a syntax error in the "Full example with terraform-aws-dynamic-subnets" code that results in a terraform plan failure.

what

• The example presented with dynamic-subnets generates a syntax error during terraform plan

why

• Improves documentation reliability

[vanastassiou]

Hilariously, @cloudpossebot reverted my fix in the Auto Format step.

[joe-niland]

Hi @vanastassiou if you reapply it to readme.yaml it should work.

[vanastassiou]

Thanks @joe-niland, I've pushed that change.

[joe-niland]

/test all

[joe-niland]

Thanks @vanastassiou - released as https://github.com/cloudposse/terraform-aws-vpc/releases/tag/1.1.1