github
Update Terraform.gitignore to include Terragrunt
Reasons for making this change:
Terragrunt is a thin wrapper tool for Terraform: https://terragrunt.gruntwork.io/
It makes sense to add this to the Terraform template, because if one is using Terragrunt, then by default Terraform is also being used. Terragrunt is popular and increasingly becoming a necessary wrapper for complex Terraform operations.
Links to documentation supporting these rule changes:
Documentation which highlights the caching folder: https://terragrunt.gruntwork.io/docs/features/caching/#clearing-the-terragrunt-cache
The generate command which creates arbitrary generated* files in the current working directory: https://terragrunt.gruntwork.io/docs/reference/config-blocks-and-attributes/#generate
*Reopening #3508
