Ignore terragrunt cache

[costaparas]

This excludes the common/default cache location from source control

Reasons for making this change:

Terragrunt is a convenient tool used when using terraform. The cache directory is not needed in source control; as per the docs, it can be safely deleted as it will be re-created automatically when needed.

Links to documentation supporting these rule changes:

Here is a sample .gitignore from the terragrunt project itself: https://github.com/gruntwork-io/terragrunt/blob/master/.gitignore

Reference docs about the cache directory: https://terragrunt.gruntwork.io/docs/features/caching/

[wirecat]

👋 Hi @costaparas. We don't typically add tooling specific ignores into the more generic templates. Would you be open to creating a template in community/ for terragrunt instead?

[costaparas]

👋 Hi @costaparas. We don't typically add tooling specific ignores into the more generic templates. Would you be open to creating a template in community/ for terragrunt instead?

Updated accordingly @wirecat

[wirecat]

@costaparas Thank you for the change and contributing to gitignore!