docs: add a required input to readme

[ebi-yade]

what

Just as shown in the code

why

I copied, pasted, modified, and applied the code; then, I got an error.

references

The input docs of the module thereof: https://github.com/cloudposse/terraform-aws-ecs-web-app#inputs

[ebi-yade]

Hello,

I don't know why but my commits have been reverted by the AutoFormat action. Could you check what was wrong and correct them, if possible, please?

[jamengual]

Please do the changes on the doc to the Readme.yaml file instead.

[ebi-yade]

I got it, thanks!

And I've updated them now.

[Gowiem]

@ebi-yade this PR is quite old and is a small change, so I'm inclined to close it. Please reopen and bring it up-to-date if it is still a change you would like to see. Thanks!